Chapter 9 - Momentum w./ QuickCheck Questions

Size: px
Start display at page:

Download "Chapter 9 - Momentum w./ QuickCheck Questions"

Transcription

1 Chapter 9 - Momentum w./ QuickCheck Questions 2015 Pearson Education, Inc. Anastasia Ierides Department of Physics and Astronomy University of New Mexico October 15, 2015

2 Review of Last Time Torque - rotational equivalent to force Static equilibrium - net torque and net force have to both be zero Center of gravity & natural axis of rotation Hooke s law, Young s modulus, tensile stress and strain Elasticity of material; spring-like behavior

3 In Chapter 4-7 Learned about Newton s 3 rd law

4 In Chapter 4-7 Learned about Newton s 3 rd law Learned that when objects interact, the applied force from one object on another is equal in magnitude, but opposite in direction

5 In Chapter 4-7 Learned about Newton s 3 rd law Learned that when objects interact, the applied force from one object on another is equal in magnitude, but opposite in direction Here we apply this logic to understand how interacting objects affect each other s motion

6 In Chapter 4-7 Learned about Newton s 3 rd law Learned that when objects interact, the applied force from one object on another is equal in magnitude, but opposite in direction Here we apply this logic to understand how interacting objects affect each other s motion In particular, their momentum

7 Stop To Think A hammer hits a nail. The force of the nail on the hammer is A. Greater than the force of the hammer on the nail. B. Less than the force of the hammer on the nail. C. Equal to the force of the hammer on the nail. D. Zero.

8 Stop To Think A hammer hits a nail. The force of the nail on the hammer is A. Greater than the force of the hammer on the nail. B. Less than the force of the hammer on the nail. C. Equal to the force of the hammer on the nail. D. Zero. The force of the hammer on the nail and the force of the nail on the hammer are the two members of the action/ reaction pair of Newton s 3rd law. They must have the same magnitude.

9 Stop To Think A hammer hits a nail. The force of the nail on the hammer is A. Greater than the force of the hammer on the nail. B. Less than the force of the hammer on the nail. C. Equal to the force of the hammer on the nail. D. Zero. The force of the hammer on the nail and the force of the nail on the hammer are the two members of the action/ reaction pair of Newton s 3rd law. They must have the same magnitude.

10 Collisions and Elasticity A collision is a short-duration interaction between two objects

11 Collisions and Elasticity A collision is a short-duration interaction between two objects Objects are compressed during a collision, requiring time to re-expand

12 Collisions and Elasticity A collision is a short-duration interaction between two objects Objects are compressed during a collision, requiring time to re-expand The duration of a collision depends on the material the objects are made from

13 Collisions and Elasticity A collision is a short-duration interaction between two objects Objects are compressed during a collision, requiring time to re-expand The duration of a collision depends on the material the objects are made from The amount of compression is a measure of the magnitude of the force exerted on the object

14 Impulse - Kicking a Ball

15 Impulse - Kicking a Ball Compression occurs during contact due to the force between the two objects

16 Impulse - Kicking a Ball Compression occurs during contact due to the force between the two objects This force is called the impulse force - large force exerted over a small time interval

17 Impulse - Kicking a Ball The effect of an impulsive force is proportional to the area under the forceversus-time curve

18 Impulse - Kicking a Ball The area is called the impulse J of the force.

19 Impulse - Kicking a Ball The area is called the impulse J of the force. To simplify, look at the average force

20 Impulse It is useful to think of the collision in terms of an average force F avg

21 Impulse It is useful to think of the collision in terms of an average force F avg F avg is defined as the constant force that has the same duration Δt yielding the same area under the curve

22 Impulse

23 Impulse Impulse has units of N s or kg m/s (preferred)

24 Impulse Impulse has units of N s or kg m/s (preferred) It is a vector quantity pointing in the same direction as the average force, F avg,

25 Impulse Impulse has units of N s or kg m/s (preferred) It is a vector quantity pointing in the same direction as the average force, F avg,

26 Example 9.1: Finding the impulse on a bouncing ball A rubber ball experiences the force shown in the figure as it bounces off the floor. a. What is the impulse on the ball? b. What is the average force on the ball?

27 Example 9.1: Finding the impulse on a bouncing ball A rubber ball experiences the force shown in the figure as it bounces off the floor. a. What is the impulse on the ball? b. What is the average force on the ball? PREPARE The impulse is the area under the force curve. Here the shape of the graph is triangular, so we ll need to use the fact that the area of a triangle is 1/2 height base.

28 Example 9.1: Finding the impulse on a bouncing ball SOLVE a. The impulse is

29 Example 9.1: Finding the impulse on a bouncing ball SOLVE a. The impulse is b. From J = F avg t, we can find the average force that would give this same impulse:

30 Example 9.1: Finding the impulse on a bouncing ball SOLVE a. The impulse is b. From J = F avg t, we can find the average force that would give this same impulse:

31 Example 9.1: Finding the impulse on a bouncing ball SOLVE a. The impulse is b. From J = F avg t, we can find the average force that would give this same impulse: ASSESS The average value of the force is half the max value, not surprising for a triangular force.

32 Stop To Think 9.1 Graph A is the force-versus-time graph for a hockey stick hitting a 160 g puck. Graph B is the force-versus-time graph for a golf club hitting a 46 g golf ball. Which force delivers the greater impulse? A. Force A B. Force B C. Both forces deliver the same impulse.

33 Stop To Think 9.1 Graph A is the force-versus-time graph for a hockey stick hitting a 160 g puck. Graph B is the force-versus-time graph for a golf club hitting a 46 g golf ball. Which force delivers the greater impulse? A. Force A B. Force B C. Both forces deliver the same impulse.

34 Stop To Think 9.1 Graph A is the force-versus-time graph for a hockey stick hitting a 160 g puck. Graph B is the force-versus-time graph for a golf club hitting a 46 g golf ball. Which force delivers the greater impulse? JA = (300 N) (.005 s) = 1.5 kg m/s JB = (150 N) (.010 s) = 1.5 kg m/s A. Force A B. Force B C. Both forces deliver the same impulse.

35 Stop To Think 9.1 Graph A is the force-versus-time graph for a hockey stick hitting a 160 g puck. Graph B is the force-versus-time graph for a golf club hitting a 46 g golf ball. Which force delivers the greater impulse? JA = (300 N) (.005 s) = 1.5 kg m/s JB = (150 N) (.010 s) = 1.5 kg m/s A. Force A B. Force B C. Both forces deliver the same impulse.

36 Momentum The more mass an object has, the more force is required to cause it to accelerate - Newton s 2 nd

37 Momentum The more mass an object has, the more force is required to cause it to accelerate - Newton s 2 nd

38 Momentum The more mass an object has, the more force is required to cause it to accelerate - Newton s 2 nd

39 Momentum The more mass an object has, the more force is required to cause it to accelerate - Newton s 2 nd

40 Momentum Rearranging the terms we find that

41 Momentum Rearranging the terms we find that Momentum is the product of the object s mass and velocity

42 Momentum Rearranging the terms we find that Momentum is the product of the object s mass and velocity Units of kg m/s

43 Momentum

44 Momentum The magnitude of an object s momentum is the product of the object s mass and speed

45 Momentum

46 Impulse-Momentum We saw that, where the right side is the change in the momentum of an object

47 Impulse-Momentum We saw that, where the right side is the change in the momentum of an object We know that the area under the force-versustime curve, or the product of the average force over the time interval it is applied, is the impulse

48 Impulse-Momentum We can deduce then, that impulse and momentum are related as

49 Impulse-Momentum We can deduce then, that impulse and momentum are related as

50 Impulse-Momentum We can deduce then, that impulse and momentum are related as The impulse-momentum theory states that an impulse delivered to an object causes the object s momentum to change

51 QuickCheck Question 9.1 The cart s change of momentum Δp x is A. 20 kg m/s B. 10 kg m/s C. 0 kg m/s D. 10 kg m/s E. 30 kg m/s

52 QuickCheck Question 9.1 The cart s change of momentum Δp x is A. 20 kg m/s B. 10 kg m/s C. 0 kg m/s D. 10 kg m/s E. 30 kg m/s Δp x = 10 kg m/s ( 20 kg m/s) = 30 kg m/s

53 QuickCheck Question 9.1 The cart s change of momentum Δp x is A. 20 kg m/s B. 10 kg m/s C. 0 kg m/s D. 10 kg m/s E. 30 kg m/s Δp x = 10 kg m/s ( 20 kg m/s) = 30 kg m/s Negative initial momentum because motion is to the left and v x < 0.

54 QuickCheck Question 9.1 The cart s change of momentum Δp x is A. 20 kg m/s B. 10 kg m/s C. 0 kg m/s D. 10 kg m/s E. 30 kg m/s Δp x = 10 kg m/s ( 20 kg m/s) = 30 kg m/s Negative initial momentum because motion is to the left and v x < 0.

55 QuickCheck Question 9.2 A 2.0 kg object moving to the right with speed 0.50 m/s experiences the force shown. What are the object s speed and direction after the force ends? A m/s left B. At rest C m/s right D. 1.0 m/s right E. 2.0 m/s right

56 QuickCheck Question 9.2 A 2.0 kg object moving to the right with speed 0.50 m/s experiences the force shown. What are the object s speed and direction after the force ends? A m/s left B. At rest C m/s right D. 1.0 m/s right E. 2.0 m/s right J x =

57 QuickCheck Question 9.2 A 2.0 kg object moving to the right with speed 0.50 m/s experiences the force shown. What are the object s speed and direction after the force ends? A m/s left B. At rest C m/s right D. 1.0 m/s right J x = E. 2.0 m/s right = 1 kg m/s

58 QuickCheck Question 9.2 A 2.0 kg object moving to the right with speed 0.50 m/s experiences the force shown. What are the object s speed and direction after the force ends? A m/s left B. At rest C m/s right D. 1.0 m/s right J x = E. 2.0 m/s right = 1 kg m/s J x = Δp x = m (vf - vi) vf = J x /m + vi

59 QuickCheck Question 9.2 A 2.0 kg object moving to the right with speed 0.50 m/s experiences the force shown. What are the object s speed and direction after the force ends? A m/s left B. At rest C m/s right D. 1.0 m/s right E. 2.0 m/s right = 1 kg m/s vf = J x /m + vi = (1 kg m/s)/(2.0 kg) + (0.5 m/s) = 1 m/s J x = J x = Δp x = m (vf - vi) vf = J x /m + vi

60 QuickCheck Question 9.2 A 2.0 kg object moving to the right with speed 0.50 m/s experiences the force shown. What are the object s speed and direction after the force ends? A m/s left B. At rest C m/s right D. 1.0 m/s right J x = E. 2.0 m/s right = 1 kg m/s vf = J x /m + vi = (1 kg m/s)/(2.0 kg) + (0.5 m/s) = 1 m/s J x = Δp x = m (vf - vi) vf = J x /m + vi

61 QuickCheck Question 9.4 A force pushes the cart for 1 s, starting from rest. To achieve the same speed with a force half as big, the force would need to push for A. 1/4 s B. 1/2 s C. 1 s D. 2 s E. 4 s

62 QuickCheck Question 9.4 A force pushes the cart for 1 s, starting from rest. To achieve the same speed with a force half as big, the force would need to push for A. 1/4 s B. 1/2 s C. 1 s D. 2 s E. 4 s Remember: Fnew =1/2 Fold

63 QuickCheck Question 9.4 A force pushes the cart for 1 s, starting from rest. To achieve the same speed with a force half as big, the force would need to push for A. 1/4 s B. 1/2 s C. 1 s D. 2 s E. 4 s Remember: F 1/Δt Fnew =1/2 Fold

64 QuickCheck Question 9.4 A force pushes the cart for 1 s, starting from rest. To achieve the same speed with a force half as big, the force would need to push for A. 1/4 s B. 1/2 s C. 1 s D. 2 s E. 4 s Remember: F 1/Δt Fnew =1/2 Fold Fnew Fold = 1/Δtnew 1/Δtold = Δtold =1/2 Δtnew Δtnew = 2 Δtold

65 QuickCheck Question 9.4 A force pushes the cart for 1 s, starting from rest. To achieve the same speed with a force half as big, the force would need to push for A. 1/4 s B. 1/2 s C. 1 s D. 2 s E. 4 s Remember: F 1/Δt Fnew =1/2 Fold Fnew Fold = 1/Δtnew 1/Δtold = Δtold Δtnew =1/2 Δtnew = 2 Δtold

66 QuickCheck Question 9.5 A light plastic cart and a heavy steel cart are both pushed with the same force for 1.0 s, starting from rest. After the force is removed, the momentum of the light plastic cart is that of the heavy steel cart. A. Greater than B. Equal to C. Less than D. Can t say. It depends on how big the force is.

67 QuickCheck Question 9.5 A light plastic cart and a heavy steel cart are both pushed with the same force for 1.0 s, starting from rest. After the force is removed, the momentum of the light plastic cart is that of the heavy steel cart. Same force, same time same impulse Same impulse same change of momentum A. Greater than B. Equal to C. Less than D. Can t say. It depends on how big the force is.

68 QuickCheck Question 9.5 A light plastic cart and a heavy steel cart are both pushed with the same force for 1.0 s, starting from rest. After the force is removed, the momentum of the light plastic cart is that of the heavy steel cart. Same force, same time same impulse Same impulse same change of momentum A. Greater than B. Equal to C. Less than D. Can t say. It depends on how big the force is.

69 QuickCheck 9.6 Two 1.0 kg stationary cue balls are struck by cue sticks. The cues exert the forces shown. Which ball has the greater final speed? 10 N A. Ball 1 B. Ball 2 C. Both balls have the same final speed.

70 QuickCheck 9.6 Two 1.0 kg stationary cue balls are struck by cue sticks. The cues exert the forces shown. Which ball has the greater final speed? Remember: Change in momentum is due to the impulse delivered which is the area under the curve. 10 N A. Ball 1 B. Ball 2 C. Both balls have the same final speed.

71 QuickCheck 9.6 Two 1.0 kg stationary cue balls are struck by cue sticks. The cues exert the forces shown. Which ball has the greater final speed? Remember: Change in momentum is due to the impulse delivered which is the area under the curve. Area = 0.2 kg m/s 10 N Area = 0.2 kg m/s A. Ball 1 B. Ball 2 C. Both balls have the same final speed.

72 QuickCheck 9.6 Two 1.0 kg stationary cue balls are struck by cue sticks. The cues exert the forces shown. Which ball has the greater final speed? Remember: Change in momentum is due to the impulse delivered which is the area under the curve. Area = 0.2 kg m/s 10 N Area = 0.2 kg m/s A. Ball 1 B. Ball 2 C. Both balls have the same final speed.

73 Impulse-Momentum

74 Impulse-Momentum 2 dimensions? components!

75 Impulse-Momentum Theory Tells us that the average force needed to stop an object is inversely proportional to the duration of the collision

76 Impulse-Momentum Theory Tells us that the average force needed to stop an object is inversely proportional to the duration of the collision

77 Impulse-Momentum Theory Tells us that the average force needed to stop an object is inversely proportional to the duration of the collision If the duration of the collision can be increased, the force of the impact will be decreased

78 Hedgehogs Hedgehogs have been observed to fall out of trees on purpose to get to the ground!

79 Hedgehogs Hedgehogs have been observed to fall out of trees on purpose to get to the ground! Their spines help cushion their fall by increasing the time it takes for the animal to come to rest when it falls off of a tree.

80 Momentum & Impulse

81 Total Momentum

82 Total Momentum If there is a system of particles moving, then the system as a whole has an overall momentum

83 Total Momentum If there is a system of particles moving, then the system as a whole has an overall momentum The total momentum of a system of particles is the vector sum of the momenta of the individual particles:

84 Impulse Approximation The impulse approximation states that we can ignore the small forces that act during the brief time of the impulsive force We consider only the momenta and velocities immediately before and immediately after the collisions

85 Solving Momentum and Impulse Problems

86 Example 9.3: Force in hitting a baseball A 150 g baseball is thrown with a speed of 20 m/s. It is hit straight back toward the pitcher at a speed of 40 m/s. The impulsive force of the bat on the ball has the shape shown in the figure. What is the maximum force F max that the bat exerts on the ball? What is the average force that the bat exerts on the ball?

87 Example 9.3: Force in hitting a baseball PREPARE We can model the interaction as a collision. The figure is a before-and-after visual overview in which the steps from Tactics Box 9.1 are explicitly noted. Because F x is positive (a force to the right), we know the ball was initially moving toward the left and is hit back toward the right. Thus we converted the statements about speeds into information about velocities, with (v x ) i negative.

88 Example 9.3: Force in hitting a baseball SOLVE We want to use the impulse-momentum theorem to find the mathematical solution:

89 Example 9.3: Force in hitting a baseball SOLVE We want to use the impulse-momentum theorem to find the mathematical solution: We know the velocities before and after the collision, so we can find the change in the ball s momentum:

90 Example 9.3: Force in hitting a baseball SOLVE We want to use the impulse-momentum theorem to find the mathematical solution: We know the velocities before and after the collision, so we can find the change in the ball s momentum:

91 Example 9.3: Force in hitting a baseball SOLVE The force curve is a triangle with height F max and width 0.60 ms. As in Example 9.1, the area under the curve is

92 Example 9.3: Force in hitting a baseball SOLVE The force curve is a triangle with height F max and width 0.60 ms. As in Example 9.1, the area under the curve is

93 Example 9.3: Force in hitting a baseball SOLVE The force curve is a triangle with height F max and width 0.60 ms. As in Example 9.1, the area under the curve is According to the impulse-momentum theorem, px = Jx, so we have

94 Example 9.3: Force in hitting a baseball SOLVE The force curve is a triangle with height F max and width 0.60 ms. As in Example 9.1, the area under the curve is According to the impulse-momentum theorem, px = Jx, so we have

95 Example 9.3: Force in hitting a baseball SOLVE Thus the maximum force is

96 Example 9.3: Force in hitting a baseball SOLVE Thus the maximum force is

97 Example 9.3: Force in hitting a baseball SOLVE Thus the maximum force is We find that the average force, which depends on the collision duration t = s, has the smaller value:

98 Example 9.3: Force in hitting a baseball SOLVE Thus the maximum force is We find that the average force, which depends on the collision duration t = s, has the smaller value:

99 Example 9.3: Force in hitting a baseball SOLVE Thus the maximum force is We find that the average force, which depends on the collision duration t = s, has the smaller value: ASSESS F max is a large force, but quite typical of the impulsive forces during collisions.

100 Conservation of Momentum The forces on the 2 balls have equal magnitude but opposite directions (Newton s 3 rd )

101 Conservation of Momentum The forces on the 2 balls have equal magnitude but opposite directions (Newton s 3 rd )

102 Conservation of Momentum The forces on the 2 balls have equal magnitude but opposite directions (Newton s 3 rd ) If the momentum of ball 1 increases, the momentum of ball 2 will decrease by the same amount

103 Conservation of Momentum The total momentum of the system is conserved

104 Conservation of Momentum The total momentum of the system is conserved The law of conservation of momentum states that there is no change in the total momentum of system experiencing internal forces, forces that act only between particles within a system

105 QuickCheck Question 9.7 You awake in the night to find that your living room is on fire. Your one chance to save yourself is to throw something that will hit the back of your bedroom door and close it, giving you a few seconds to escape out the window. You happen to have both a sticky ball of clay and a super-bouncy Superball next to your bed, both the same size and same mass. You ve only time to throw one. Which will it be? Your life depends on making the right choice! A. Throw the Superball. B. Throw the ball of clay. C. It doesn t matter. Throw either.

106 QuickCheck Question 9.7 You awake in the night to find that your living room is on fire. Your one chance to save yourself is to throw something that will hit the back of your bedroom door and close it, giving you a few seconds to escape out the window. You happen to have both a sticky ball of clay and a super-bouncy Superball next to your bed, both the same size and same mass. You ve only time to throw one. Which will it be? Your life depends on making the right choice! Larger Δp more impulse to door A. Throw the Superball. B. Throw the ball of clay. C. It doesn t matter. Throw either.

107 QuickCheck Question 9.7 You awake in the night to find that your living room is on fire. Your one chance to save yourself is to throw something that will hit the back of your bedroom door and close it, giving you a few seconds to escape out the window. You happen to have both a sticky ball of clay and a super-bouncy Superball next to your bed, both the same size and same mass. You ve only time to throw one. Which will it be? Your life depends on making the right choice! Larger Δp more impulse to door A. Throw the Superball. B. Throw the ball of clay. C. It doesn t matter. Throw either.

108 QuickCheck Question 9.8 A mosquito and a truck have a head-on collision. Splat! Which has a larger change of momentum? A. The mosquito B. The truck C. They have the same change of momentum. D. Can t say without knowing their initial velocities.

109 QuickCheck Question 9.8 A mosquito and a truck have a head-on collision. Splat! Which has a larger change of momentum? A. The mosquito B. The truck C. They have the same change of momentum. D. Can t say without knowing their initial velocities. Momentum is conserved, so Δp mosquito + Δp truck = 0. Equal magnitude (but opposite sign) changes in momentum.

110 QuickCheck Question 9.8 A mosquito and a truck have a head-on collision. Splat! Which has a larger change of momentum? A. The mosquito B. The truck C. They have the same change of momentum. D. Can t say without knowing their initial velocities. Momentum is conserved, so Δp mosquito + Δp truck = 0. Equal magnitude (but opposite sign) changes in momentum.

111 Law of Conservation of Momentum External forces are forces from agents outside the system

112 Law of Conservation of Momentum External forces are forces from agents outside the system They can change the momentum of the system

113 Law of Conservation of Momentum External forces are forces from agents outside the system They can change the momentum of the system An isolated system is a system with no net external force acting on it

114 Law of Conservation of Momentum The change in the total momentum is

115 Law of Conservation of Momentum The change in the total momentum is If the net force due to external forces is 0, then the change in the total momentum is 0

116 Law of Conservation of Momentum

117 Law of Conservation of Momentum The total momentum of a system after an interaction is equal to the total momentum before the interaction and is written as

118 Law of Conservation of Momentum The total momentum of a system after an interaction is equal to the total momentum before the interaction and is written as

119 In 2 Dimensions Since momentum is a vector, we can rewrite the law of conservation of momentum for an isolated system:

120 Solving Law of Conservation of Momentum Problems

121 Solving Law of Conservation of Momentum Problems

122 It Depends on the System Goal: choose a system with conserved momentum

123 It Depends on the System Goal: choose a system with conserved momentum If we choose just the person, there is a nonzero net force on the system

124 It Depends on the System Goal: choose a system with conserved momentum If we choose just the person, there is a nonzero net force on the system If we choose the system to be the person and the cart, the net force is zero and the momentum is conserved

125 Example 9.5: Speed of Ice Skaters pushing off Two ice skaters, Sandra and David, stand facing each other on frictionless ice. Sandra has a mass of 45 kg, David a mass of 80 kg. They then push off from each other. After the push, Sandra moves off at a speed of 2.2 m/s. What is David s speed?

126 Example 9.5: Speed of Ice Skaters pushing off PREPARE The two skaters interact with each other, but they form an isolated system because, for each skater, the upward normal force of the ice balances their downward weight force to make Thus the total momentum of the system of the two skaters is conserved. The figure shows a before-and-after visual overview for the two skaters. The total momentum before they push off is zero because both skaters are at rest. Consequently, the total momentum will still be 0 after they push off.

127 Example 9.5: Speed of Ice Skaters pushing off SOLVE Since the motion is only in the x-direction, we ll need to consider only x-components of momentum. We write Sandra s initial momentum as (p Sx ) i = m S (v Sx ) i, where m S is her mass and (v Sx ) i her initial velocity. Similarly, we write David s initial momentum as (p Dx ) i = m D (v Dx ) i. Both these momenta are zero because both skaters are initially at rest.

128 Example 9.5: Speed of Ice Skaters pushing off SOLVE We can now apply the mathematical statement of momentum conservation, Equation Writing the final momentum of Sandra as m S (v Sx ) f and that of David as m D (v Dx ) f, we have

129 Example 9.5: Speed of Ice Skaters pushing off SOLVE We can now apply the mathematical statement of momentum conservation, Equation Writing the final momentum of Sandra as m S (v Sx ) f and that of David as m D (v Dx ) f, we have

130 Example 9.5: Speed of Ice Skaters pushing off SOLVE Solving for (v Dx ) f, we find

131 Example 9.5: Speed of Ice Skaters pushing off SOLVE Solving for (v Dx ) f, we find David moves backward with a speed of 1.2 m/s. Notice that we didn t need to know any details about the force between David and Sandra in order to find David s final speed. Conservation of momentum mandates this result.

132 Example 9.5: Speed of Ice Skaters pushing off SOLVE Solving for (v Dx ) f, we find David moves backward with a speed of 1.2 m/s. Notice that we didn t need to know any details about the force between David and Sandra in order to find David s final speed. Conservation of momentum mandates this result. ASSESS It seems reasonable that Sandra, whose mass is less than David s, has the greater final speed.

133 Interactions Between Particles Two types of collisions

134 Interactions Between Particles Two types of collisions 1. Elastic - particles collide and separate from one another

135 Interactions Between Particles Two types of collisions 1. Elastic - particles collide and separate from one another 2. Inelastic - particles collide and stick to one another

136 Interactions Between Particles Two types of collisions 1. Elastic - particles collide and separate from one another 2. Inelastic - particles collide and stick to one another Explosions - particles move apart from one another in the opposite direction

137 Explosions! An explosion is when the particles of the system move apart after a brief, intense interaction; opposite of a collision

138 Explosions! An explosion is when the particles of the system move apart after a brief, intense interaction; opposite of a collision The forces are internal forces and if the system is isolated, the total momentum is conserved

139 QuickCheck Question 9.10 The two boxes are on a frictionless surface. They had been sitting together at rest, but an explosion between them has just pushed them apart. How fast is the 2-kg box going? A. 1 m/s B. 2 m/s C. 4 m/s D. 8 m/s E. There s not enough information to tell.

140 QuickCheck Question 9.10 The two boxes are on a frictionless surface. They had been sitting together at rest, but an explosion between them has just pushed them apart. How fast is the 2-kg box going? A. 1 m/s B. 2 m/s C. 4 m/s D. 8 m/s E. There s not enough information to tell.

141 Inelastic Collisions A perfectly inelastic collision is a collision in which the two objects stick together and move with a common final velocity

142 Inelastic Collisions A perfectly inelastic collision is a collision in which the two objects stick together and move with a common final velocity Examples include clay hitting the floor and a bullet embedding itself in wood

143 QuickCheck Question 9.11 The 1-kg box is sliding along a frictionless surface. It collides with and sticks to the 2-kg box. Afterward, the speed of the two boxes is A. 0 m/s B. 1 m/s C. 2 m/s D. 3 m/s E. There s not enough information to tell.

144 QuickCheck Question 9.11 The 1-kg box is sliding along a frictionless surface. It collides with and sticks to the 2-kg box. Afterward, the speed of the two boxes is A. 0 m/s B. 1 m/s C. 2 m/s D. 3 m/s E. There s not enough information to tell.

145 Momentum and Collisions in 2 Dimensions When the motion of the collisions occur in two dimensions, we must solve for each component of the momentum:

146 Momentum and Collisions in 2 Dimensions When the motion of the collisions occur in two dimensions, we must solve for each component of the momentum: In these collisions, the individual momenta can change but the total momentum does not.

147 Summary

148 Summary

149 Summary

150 Summary

151 Summary

152 Summary

153 Things that are due Reading Quiz #9 Due October 20, 2015 by 4:59 pm Homework #6 Due October 21, 2015 at 11:59 pm Reading Quiz #10 Due October 22, 2015 by 4:59 pm

154 QUESTIONS?

Exam Three Momentum Concept Questions

Exam Three Momentum Concept Questions Exam Three Momentum Concept Questions Isolated Systems 4. A car accelerates from rest. In doing so the absolute value of the car's momentum changes by a certain amount and that of the Earth changes by:

More information

AP physics C Web Review Ch 6 Momentum

AP physics C Web Review Ch 6 Momentum Name: Class: _ Date: _ AP physics C Web Review Ch 6 Momentum Please do not write on my tests Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The dimensional

More information

Chapter 7: Momentum and Impulse

Chapter 7: Momentum and Impulse Chapter 7: Momentum and Impulse 1. When a baseball bat hits the ball, the impulse delivered to the ball is increased by A. follow through on the swing. B. rapidly stopping the bat after impact. C. letting

More information

Problem Set #8 Solutions

Problem Set #8 Solutions MASSACHUSETTS INSTITUTE OF TECHNOLOGY Physics Department 8.01L: Physics I November 7, 2015 Prof. Alan Guth Problem Set #8 Solutions Due by 11:00 am on Friday, November 6 in the bins at the intersection

More information

Kinetic Energy (A) stays the same stays the same (B) increases increases (C) stays the same increases (D) increases stays the same.

Kinetic Energy (A) stays the same stays the same (B) increases increases (C) stays the same increases (D) increases stays the same. 1. A cart full of water travels horizontally on a frictionless track with initial velocity v. As shown in the diagram, in the back wall of the cart there is a small opening near the bottom of the wall

More information

Chapter 7 Momentum and Impulse

Chapter 7 Momentum and Impulse Chapter 7 Momentum and Impulse Collisions! How can we describe the change in velocities of colliding football players, or balls colliding with bats?! How does a strong force applied for a very short time

More information

Work, Energy & Momentum Homework Packet Worksheet 1: This is a lot of work!

Work, Energy & Momentum Homework Packet Worksheet 1: This is a lot of work! Work, Energy & Momentum Homework Packet Worksheet 1: This is a lot of work! 1. A student holds her 1.5-kg psychology textbook out of a second floor classroom window until her arm is tired; then she releases

More information

Physics 125 Practice Exam #3 Chapters 6-7 Professor Siegel

Physics 125 Practice Exam #3 Chapters 6-7 Professor Siegel Physics 125 Practice Exam #3 Chapters 6-7 Professor Siegel Name: Lab Day: 1. A concrete block is pulled 7.0 m across a frictionless surface by means of a rope. The tension in the rope is 40 N; and the

More information

Tennessee State University

Tennessee State University Tennessee State University Dept. of Physics & Mathematics PHYS 2010 CF SU 2009 Name 30% Time is 2 hours. Cheating will give you an F-grade. Other instructions will be given in the Hall. MULTIPLE CHOICE.

More information

PRELAB: NEWTON S 3 RD LAW AND MOMENTUM CONSERVATION

PRELAB: NEWTON S 3 RD LAW AND MOMENTUM CONSERVATION Newton s 3rd Law and Momentum Conservation, p./ PRELAB: NEWTON S 3 RD LAW AND MOMENTUM CONSERVATION Read over the lab and then answer the following questions about the procedures:. Write down the definition

More information

Physics 2A, Sec B00: Mechanics -- Winter 2011 Instructor: B. Grinstein Final Exam

Physics 2A, Sec B00: Mechanics -- Winter 2011 Instructor: B. Grinstein Final Exam Physics 2A, Sec B00: Mechanics -- Winter 2011 Instructor: B. Grinstein Final Exam INSTRUCTIONS: Use a pencil #2 to fill your scantron. Write your code number and bubble it in under "EXAM NUMBER;" an entry

More information

A uranium nucleus (at rest) undergoes fission and splits into two fragments, one heavy and the other light. Which fragment has the greater speed?

A uranium nucleus (at rest) undergoes fission and splits into two fragments, one heavy and the other light. Which fragment has the greater speed? A uranium nucleus (at rest) undergoes fission and splits into two fragments, one heavy and the other light. Which fragment has the greater speed? 1 2 PHYS 1021: Chap. 9, Pg 2 Page 1 1 A uranium nucleus

More information

Exam 2 is at 7 pm tomorrow Conflict is at 5:15 pm in 151 Loomis

Exam 2 is at 7 pm tomorrow Conflict is at 5:15 pm in 151 Loomis * By request, but I m not vouching for these since I didn t write them Exam 2 is at 7 pm tomorrow Conflict is at 5:15 pm in 151 Loomis There are extra office hours today & tomorrow Lots of practice exams

More information

LAB 4: MOMENTUM AND COLLISIONS

LAB 4: MOMENTUM AND COLLISIONS 1 Name Date Day/Time of Lab Partner(s) Lab TA LAB 4: MOMENTUM AND COLLISIONS NEWTON S THIRD LAW OBJECTIVES To examine action-reaction force pairs To examine collisions and relate the law of conservation

More information

F N A) 330 N 0.31 B) 310 N 0.33 C) 250 N 0.27 D) 290 N 0.30 E) 370 N 0.26

F N A) 330 N 0.31 B) 310 N 0.33 C) 250 N 0.27 D) 290 N 0.30 E) 370 N 0.26 Physics 23 Exam 2 Spring 2010 Dr. Alward Page 1 1. A 250-N force is directed horizontally as shown to push a 29-kg box up an inclined plane at a constant speed. Determine the magnitude of the normal force,

More information

9. Momentum and Collisions in One Dimension*

9. Momentum and Collisions in One Dimension* 9. Momentum and Collisions in One Dimension* The motion of objects in collision is difficult to analyze with force concepts or conservation of energy alone. When two objects collide, Newton s third law

More information

Chapter 6 Work and Energy

Chapter 6 Work and Energy Chapter 6 WORK AND ENERGY PREVIEW Work is the scalar product of the force acting on an object and the displacement through which it acts. When work is done on or by a system, the energy of that system

More information

AP Physics C Fall Final Web Review

AP Physics C Fall Final Web Review Name: Class: _ Date: _ AP Physics C Fall Final Web Review Multiple Choice Identify the choice that best completes the statement or answers the question. 1. On a position versus time graph, the slope of

More information

Review Vocabulary force: a push or a pull. Vocabulary Newton s third law of motion

Review Vocabulary force: a push or a pull. Vocabulary Newton s third law of motion Standard 7.3.17: Investigate that an unbalanced force, acting on an object, changes its speed or path of motion or both, and know that if the force always acts toward the same center as the object moves,

More information

physics 111N work & energy

physics 111N work & energy physics 111N work & energy conservation of energy entirely gravitational potential energy kinetic energy turning into gravitational potential energy gravitational potential energy turning into kinetic

More information

Free Fall: Observing and Analyzing the Free Fall Motion of a Bouncing Ping-Pong Ball and Calculating the Free Fall Acceleration (Teacher s Guide)

Free Fall: Observing and Analyzing the Free Fall Motion of a Bouncing Ping-Pong Ball and Calculating the Free Fall Acceleration (Teacher s Guide) Free Fall: Observing and Analyzing the Free Fall Motion of a Bouncing Ping-Pong Ball and Calculating the Free Fall Acceleration (Teacher s Guide) 2012 WARD S Science v.11/12 OVERVIEW Students will measure

More information

Chapter 9. particle is increased.

Chapter 9. particle is increased. Chapter 9 9. Figure 9-36 shows a three particle system. What are (a) the x coordinate and (b) the y coordinate of the center of mass of the three particle system. (c) What happens to the center of mass

More information

Physics: Principles and Applications, 6e Giancoli Chapter 4 Dynamics: Newton's Laws of Motion

Physics: Principles and Applications, 6e Giancoli Chapter 4 Dynamics: Newton's Laws of Motion Physics: Principles and Applications, 6e Giancoli Chapter 4 Dynamics: Newton's Laws of Motion Conceptual Questions 1) Which of Newton's laws best explains why motorists should buckle-up? A) the first law

More information

Review Chapters 2, 3, 4, 5

Review Chapters 2, 3, 4, 5 Review Chapters 2, 3, 4, 5 4) The gain in speed each second for a freely-falling object is about A) 0. B) 5 m/s. C) 10 m/s. D) 20 m/s. E) depends on the initial speed 9) Whirl a rock at the end of a string

More information

PHYS 117- Exam I. Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

PHYS 117- Exam I. Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. PHYS 117- Exam I Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. Car A travels from milepost 343 to milepost 349 in 5 minutes. Car B travels

More information

9. The kinetic energy of the moving object is (1) 5 J (3) 15 J (2) 10 J (4) 50 J

9. The kinetic energy of the moving object is (1) 5 J (3) 15 J (2) 10 J (4) 50 J 1. If the kinetic energy of an object is 16 joules when its speed is 4.0 meters per second, then the mass of the objects is (1) 0.5 kg (3) 8.0 kg (2) 2.0 kg (4) 19.6 kg Base your answers to questions 9

More information

C B A T 3 T 2 T 1. 1. What is the magnitude of the force T 1? A) 37.5 N B) 75.0 N C) 113 N D) 157 N E) 192 N

C B A T 3 T 2 T 1. 1. What is the magnitude of the force T 1? A) 37.5 N B) 75.0 N C) 113 N D) 157 N E) 192 N Three boxes are connected by massless strings and are resting on a frictionless table. Each box has a mass of 15 kg, and the tension T 1 in the right string is accelerating the boxes to the right at a

More information

Practice Exam Three Solutions

Practice Exam Three Solutions MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Physics Physics 8.01T Fall Term 2004 Practice Exam Three Solutions Problem 1a) (5 points) Collisions and Center of Mass Reference Frame In the lab frame,

More information

At the skate park on the ramp

At the skate park on the ramp At the skate park on the ramp 1 On the ramp When a cart rolls down a ramp, it begins at rest, but starts moving downward upon release covers more distance each second When a cart rolls up a ramp, it rises

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Vector A has length 4 units and directed to the north. Vector B has length 9 units and is directed

More information

Conservation of Momentum and Energy

Conservation of Momentum and Energy Conservation of Momentum and Energy OBJECTIVES to investigate simple elastic and inelastic collisions in one dimension to study the conservation of momentum and energy phenomena EQUIPMENT horizontal dynamics

More information

KE =? v o. Page 1 of 12

KE =? v o. Page 1 of 12 Page 1 of 12 CTEnergy-1. A mass m is at the end of light (massless) rod of length R, the other end of which has a frictionless pivot so the rod can swing in a vertical plane. The rod is initially horizontal

More information

Chapter #7 Giancoli 6th edition Problem Solutions

Chapter #7 Giancoli 6th edition Problem Solutions Chapter #7 Giancoli 6th edition Problem Solutions ü Problem #8 QUESTION: A 9300 kg boxcar traveling at 5.0 m/s strikes a second boxcar at rest. The two stick together and move off with a speed of 6.0 m/s.

More information

Experiment 7 ~ Conservation of Linear Momentum

Experiment 7 ~ Conservation of Linear Momentum Experiment 7 ~ Conservation of Linear Momentum Purpose: The purpose of this experiment is to reproduce a simple experiment demonstrating the Conservation of Linear Momentum. Theory: The momentum p of an

More information

Lecture PowerPoints. Chapter 7 Physics: Principles with Applications, 6 th edition Giancoli

Lecture PowerPoints. Chapter 7 Physics: Principles with Applications, 6 th edition Giancoli Lecture PowerPoints Chapter 7 Physics: Principles with Applications, 6 th edition Giancoli 2005 Pearson Prentice Hall This work is protected by United States copyright laws and is provided solely for the

More information

Momentum, Impulse and Momentum Change

Momentum, Impulse and Momentum Change Name: Momentum, Impulse and Momentum Change Read from Lesson 1 of the Momentum and Collisions chapter at The Physics Classroom: http://www.physicsclassroom.com/class/momentum/u4l1a.html http://www.physicsclassroom.com/class/momentum/u4l1b.html

More information

Midterm Solutions. mvr = ω f (I wheel + I bullet ) = ω f 2 MR2 + mr 2 ) ω f = v R. 1 + M 2m

Midterm Solutions. mvr = ω f (I wheel + I bullet ) = ω f 2 MR2 + mr 2 ) ω f = v R. 1 + M 2m Midterm Solutions I) A bullet of mass m moving at horizontal velocity v strikes and sticks to the rim of a wheel a solid disc) of mass M, radius R, anchored at its center but free to rotate i) Which of

More information

P211 Midterm 2 Spring 2004 Form D

P211 Midterm 2 Spring 2004 Form D 1. An archer pulls his bow string back 0.4 m by exerting a force that increases uniformly from zero to 230 N. The equivalent spring constant of the bow is: A. 115 N/m B. 575 N/m C. 1150 N/m D. 287.5 N/m

More information

If all three collisions below are totally inelastic, which one(s) will bring the car on the left to a complete halt?

If all three collisions below are totally inelastic, which one(s) will bring the car on the left to a complete halt? ConcepTest 8.1 Crash Cars I If all three collisions below are totally inelastic, which one(s) will bring the car on the left to a complete halt? 1) I 2) II 3) I and II 4) II and III 5) all three ConcepTest

More information

v v ax v a x a v a v = = = Since F = ma, it follows that a = F/m. The mass of the arrow is unchanged, and ( )

v v ax v a x a v a v = = = Since F = ma, it follows that a = F/m. The mass of the arrow is unchanged, and ( ) Week 3 homework IMPORTANT NOTE ABOUT WEBASSIGN: In the WebAssign versions of these problems, various details have been changed, so that the answers will come out differently. The method to find the solution

More information

Ground Rules. PC1221 Fundamentals of Physics I. Kinematics. Position. Lectures 3 and 4 Motion in One Dimension. Dr Tay Seng Chuan

Ground Rules. PC1221 Fundamentals of Physics I. Kinematics. Position. Lectures 3 and 4 Motion in One Dimension. Dr Tay Seng Chuan Ground Rules PC11 Fundamentals of Physics I Lectures 3 and 4 Motion in One Dimension Dr Tay Seng Chuan 1 Switch off your handphone and pager Switch off your laptop computer and keep it No talking while

More information

Lecture 17. Last time we saw that the rotational analog of Newton s 2nd Law is

Lecture 17. Last time we saw that the rotational analog of Newton s 2nd Law is Lecture 17 Rotational Dynamics Rotational Kinetic Energy Stress and Strain and Springs Cutnell+Johnson: 9.4-9.6, 10.1-10.2 Rotational Dynamics (some more) Last time we saw that the rotational analog of

More information

Mechanics 1: Conservation of Energy and Momentum

Mechanics 1: Conservation of Energy and Momentum Mechanics : Conservation of Energy and Momentum If a certain quantity associated with a system does not change in time. We say that it is conserved, and the system possesses a conservation law. Conservation

More information

NEWTON S LAWS OF MOTION

NEWTON S LAWS OF MOTION Name Period Date NEWTON S LAWS OF MOTION If I am anything, which I highly doubt, I have made myself so by hard work. Isaac Newton Goals: 1. Students will use conceptual and mathematical models to predict

More information

Chapter 3.8 & 6 Solutions

Chapter 3.8 & 6 Solutions Chapter 3.8 & 6 Solutions P3.37. Prepare: We are asked to find period, speed and acceleration. Period and frequency are inverses according to Equation 3.26. To find speed we need to know the distance traveled

More information

Answer: Same magnitude total momentum in both situations.

Answer: Same magnitude total momentum in both situations. Page 1 of 9 CTP-1. In which situation is the agnitude of the total oentu the largest? A) Situation I has larger total oentu B) Situation II C) Sae agnitude total oentu in both situations. I: v 2 (rest)

More information

PHY231 Section 2, Form A March 22, 2012. 1. Which one of the following statements concerning kinetic energy is true?

PHY231 Section 2, Form A March 22, 2012. 1. Which one of the following statements concerning kinetic energy is true? 1. Which one of the following statements concerning kinetic energy is true? A) Kinetic energy can be measured in watts. B) Kinetic energy is always equal to the potential energy. C) Kinetic energy is always

More information

1 of 7 9/5/2009 6:12 PM

1 of 7 9/5/2009 6:12 PM 1 of 7 9/5/2009 6:12 PM Chapter 2 Homework Due: 9:00am on Tuesday, September 8, 2009 Note: To understand how points are awarded, read your instructor's Grading Policy. [Return to Standard Assignment View]

More information

Physics Momentum and Impulse Car Safety Engineering (egg drop) Conservation of Momentum

Physics Momentum and Impulse Car Safety Engineering (egg drop) Conservation of Momentum Physics Momentum and Impulse Car Safety Engineering (egg drop) Intro to Momentum Conservation of Momentum Impulse Student Experience Students brainstorm the meaning of momentum. Students use different

More information

In order to describe motion you need to describe the following properties.

In order to describe motion you need to describe the following properties. Chapter 2 One Dimensional Kinematics How would you describe the following motion? Ex: random 1-D path speeding up and slowing down In order to describe motion you need to describe the following properties.

More information

Notes on Elastic and Inelastic Collisions

Notes on Elastic and Inelastic Collisions Notes on Elastic and Inelastic Collisions In any collision of 2 bodies, their net momentus conserved. That is, the net momentum vector of the bodies just after the collision is the same as it was just

More information

Lecture 07: Work and Kinetic Energy. Physics 2210 Fall Semester 2014

Lecture 07: Work and Kinetic Energy. Physics 2210 Fall Semester 2014 Lecture 07: Work and Kinetic Energy Physics 2210 Fall Semester 2014 Announcements Schedule next few weeks: 9/08 Unit 3 9/10 Unit 4 9/15 Unit 5 (guest lecturer) 9/17 Unit 6 (guest lecturer) 9/22 Unit 7,

More information

Exercises on Work, Energy, and Momentum. A B = 20(10)cos98 A B 28

Exercises on Work, Energy, and Momentum. A B = 20(10)cos98 A B 28 Exercises on Work, Energy, and Momentum Exercise 1.1 Consider the following two vectors: A : magnitude 20, direction 37 North of East B : magnitude 10, direction 45 North of West Find the scalar product

More information

Chapter 15 Collision Theory

Chapter 15 Collision Theory Chapter 15 Collision Theory 151 Introduction 1 15 Reference Frames Relative and Velocities 1 151 Center of Mass Reference Frame 15 Relative Velocities 3 153 Characterizing Collisions 5 154 One-Dimensional

More information

Lab 8: Ballistic Pendulum

Lab 8: Ballistic Pendulum Lab 8: Ballistic Pendulum Equipment: Ballistic pendulum apparatus, 2 meter ruler, 30 cm ruler, blank paper, carbon paper, masking tape, scale. Caution In this experiment a steel ball is projected horizontally

More information

5. Forces and Motion-I. Force is an interaction that causes the acceleration of a body. A vector quantity.

5. Forces and Motion-I. Force is an interaction that causes the acceleration of a body. A vector quantity. 5. Forces and Motion-I 1 Force is an interaction that causes the acceleration of a body. A vector quantity. Newton's First Law: Consider a body on which no net force acts. If the body is at rest, it will

More information

Fundamental Mechanics: Supplementary Exercises

Fundamental Mechanics: Supplementary Exercises Phys 131 Fall 2015 Fundamental Mechanics: Supplementary Exercises 1 Motion diagrams: horizontal motion A car moves to the right. For an initial period it slows down and after that it speeds up. Which of

More information

WORK DONE BY A CONSTANT FORCE

WORK DONE BY A CONSTANT FORCE WORK DONE BY A CONSTANT FORCE The definition of work, W, when a constant force (F) is in the direction of displacement (d) is W = Fd SI unit is the Newton-meter (Nm) = Joule, J If you exert a force of

More information

Physical Science Chapter 2. Forces

Physical Science Chapter 2. Forces Physical Science Chapter 2 Forces The Nature of Force By definition, a Force is a push or a pull. A Push Or A Pull Just like Velocity & Acceleration Forces have both magnitude and direction components

More information

Physics 11 Assignment KEY Dynamics Chapters 4 & 5

Physics 11 Assignment KEY Dynamics Chapters 4 & 5 Physics Assignment KEY Dynamics Chapters 4 & 5 ote: for all dynamics problem-solving questions, draw appropriate free body diagrams and use the aforementioned problem-solving method.. Define the following

More information

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Exam Name SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 1) A person on a sled coasts down a hill and then goes over a slight rise with speed 2.7 m/s.

More information

Objective: Equilibrium Applications of Newton s Laws of Motion I

Objective: Equilibrium Applications of Newton s Laws of Motion I Type: Single Date: Objective: Equilibrium Applications of Newton s Laws of Motion I Homework: Assignment (1-11) Read (4.1-4.5, 4.8, 4.11); Do PROB # s (46, 47, 52, 58) Ch. 4 AP Physics B Mr. Mirro Equilibrium,

More information

Physics Notes Class 11 CHAPTER 6 WORK, ENERGY AND POWER

Physics Notes Class 11 CHAPTER 6 WORK, ENERGY AND POWER 1 P a g e Work Physics Notes Class 11 CHAPTER 6 WORK, ENERGY AND POWER When a force acts on an object and the object actually moves in the direction of force, then the work is said to be done by the force.

More information

Forces. When an object is pushed or pulled, we say that a force is exerted on it.

Forces. When an object is pushed or pulled, we say that a force is exerted on it. Forces When an object is pushed or pulled, we say that a force is exerted on it. Forces can Cause an object to start moving Change the speed of a moving object Cause a moving object to stop moving Change

More information

Chapter 7 Homework solutions

Chapter 7 Homework solutions Chapter 7 Homework solutions 8 Strategy Use the component form of the definition of center of mass Solution Find the location of the center of mass Find x and y ma xa + mbxb (50 g)(0) + (10 g)(5 cm) x

More information

Lesson 39: Kinetic Energy & Potential Energy

Lesson 39: Kinetic Energy & Potential Energy Lesson 39: Kinetic Energy & Potential Energy Total Mechanical Energy We sometimes call the total energy of an object (potential and kinetic) the total mechanical energy of an object. Mechanical energy

More information

Unit 4 Practice Test: Rotational Motion

Unit 4 Practice Test: Rotational Motion Unit 4 Practice Test: Rotational Motion Multiple Guess Identify the letter of the choice that best completes the statement or answers the question. 1. How would an angle in radians be converted to an angle

More information

Proof of the conservation of momentum and kinetic energy

Proof of the conservation of momentum and kinetic energy Experiment 04 Proof of the conservation of momentum and kinetic energy By Christian Redeker 27.10.2007 Contents 1.) Hypothesis...3 2.) Diagram...7 3.) Method...7 3.1) Apparatus...7 3.2) Procedure...7 4.)

More information

AP Physics C. Oscillations/SHM Review Packet

AP Physics C. Oscillations/SHM Review Packet AP Physics C Oscillations/SHM Review Packet 1. A 0.5 kg mass on a spring has a displacement as a function of time given by the equation x(t) = 0.8Cos(πt). Find the following: a. The time for one complete

More information

10.1 Quantitative. Answer: A Var: 50+

10.1 Quantitative. Answer: A Var: 50+ Chapter 10 Energy and Work 10.1 Quantitative 1) A child does 350 J of work while pulling a box from the ground up to his tree house with a rope. The tree house is 4.8 m above the ground. What is the mass

More information

BHS Freshman Physics Review. Chapter 2 Linear Motion Physics is the oldest science (astronomy) and the foundation for every other science.

BHS Freshman Physics Review. Chapter 2 Linear Motion Physics is the oldest science (astronomy) and the foundation for every other science. BHS Freshman Physics Review Chapter 2 Linear Motion Physics is the oldest science (astronomy) and the foundation for every other science. Galileo (1564-1642): 1 st true scientist and 1 st person to use

More information

Review Assessment: Lec 02 Quiz

Review Assessment: Lec 02 Quiz COURSES > PHYSICS GUEST SITE > CONTROL PANEL > 1ST SEM. QUIZZES > REVIEW ASSESSMENT: LEC 02 QUIZ Review Assessment: Lec 02 Quiz Name: Status : Score: Instructions: Lec 02 Quiz Completed 20 out of 100 points

More information

Chapter 4: Newton s Laws: Explaining Motion

Chapter 4: Newton s Laws: Explaining Motion Chapter 4: Newton s Laws: Explaining Motion 1. All except one of the following require the application of a net force. Which one is the exception? A. to change an object from a state of rest to a state

More information

LAB 6: GRAVITATIONAL AND PASSIVE FORCES

LAB 6: GRAVITATIONAL AND PASSIVE FORCES 55 Name Date Partners LAB 6: GRAVITATIONAL AND PASSIVE FORCES And thus Nature will be very conformable to herself and very simple, performing all the great Motions of the heavenly Bodies by the attraction

More information

Chapter 8 Conservation of Linear Momentum. Conservation of Linear Momentum

Chapter 8 Conservation of Linear Momentum. Conservation of Linear Momentum Chapter 8 Conservation of Linear Momentum Physics 201 October 22, 2009 Conservation of Linear Momentum Definition of linear momentum, p p = m v Linear momentum is a vector. Units of linear momentum are

More information

HW Set VI page 1 of 9 PHYSICS 1401 (1) homework solutions

HW Set VI page 1 of 9 PHYSICS 1401 (1) homework solutions HW Set VI page 1 of 9 10-30 A 10 g bullet moving directly upward at 1000 m/s strikes and passes through the center of mass of a 5.0 kg block initially at rest (Fig. 10-33 ). The bullet emerges from the

More information

Newton s Laws of Motion

Newton s Laws of Motion Newton s Laws of Motion The Earth revolves around the sun in an elliptical orbit. The moon orbits the Earth in the same way. But what keeps the Earth and the moon in orbit? Why don t they just fly off

More information

Physics Notes Class 11 CHAPTER 3 MOTION IN A STRAIGHT LINE

Physics Notes Class 11 CHAPTER 3 MOTION IN A STRAIGHT LINE 1 P a g e Motion Physics Notes Class 11 CHAPTER 3 MOTION IN A STRAIGHT LINE If an object changes its position with respect to its surroundings with time, then it is called in motion. Rest If an object

More information

Physics 201 Homework 8

Physics 201 Homework 8 Physics 201 Homework 8 Feb 27, 2013 1. A ceiling fan is turned on and a net torque of 1.8 N-m is applied to the blades. 8.2 rad/s 2 The blades have a total moment of inertia of 0.22 kg-m 2. What is the

More information

Sample Questions for the AP Physics 1 Exam

Sample Questions for the AP Physics 1 Exam Sample Questions for the AP Physics 1 Exam Sample Questions for the AP Physics 1 Exam Multiple-choice Questions Note: To simplify calculations, you may use g 5 10 m/s 2 in all problems. Directions: Each

More information

Force. Force as a Vector Real Forces versus Convenience The System Mass Newton s Second Law. Outline

Force. Force as a Vector Real Forces versus Convenience The System Mass Newton s Second Law. Outline Force Force as a Vector Real Forces versus Convenience The System Mass Newton s Second Law Outline Force as a Vector Forces are vectors (magnitude and direction) Drawn so the vector s tail originates at

More information

PHY231 Section 1, Form B March 22, 2012

PHY231 Section 1, Form B March 22, 2012 1. A car enters a horizontal, curved roadbed of radius 50 m. The coefficient of static friction between the tires and the roadbed is 0.20. What is the maximum speed with which the car can safely negotiate

More information

Problem Set V Solutions

Problem Set V Solutions Problem Set V Solutions. Consider masses m, m 2, m 3 at x, x 2, x 3. Find X, the C coordinate by finding X 2, the C of mass of and 2, and combining it with m 3. Show this is gives the same result as 3

More information

Physics: Principles and Applications, 6e Giancoli Chapter 2 Describing Motion: Kinematics in One Dimension

Physics: Principles and Applications, 6e Giancoli Chapter 2 Describing Motion: Kinematics in One Dimension Physics: Principles and Applications, 6e Giancoli Chapter 2 Describing Motion: Kinematics in One Dimension Conceptual Questions 1) Suppose that an object travels from one point in space to another. Make

More information

Inertia, Forces, and Acceleration: The Legacy of Sir Isaac Newton

Inertia, Forces, and Acceleration: The Legacy of Sir Isaac Newton Inertia, Forces, and Acceleration: The Legacy of Sir Isaac Newton Position is a Vector Compare A A ball is 12 meters North of the Sun God to A A ball is 10 meters from here A vector has both a direction

More information

Newton s Laws. Physics 1425 lecture 6. Michael Fowler, UVa.

Newton s Laws. Physics 1425 lecture 6. Michael Fowler, UVa. Newton s Laws Physics 1425 lecture 6 Michael Fowler, UVa. Newton Extended Galileo s Picture of Galileo said: Motion to Include Forces Natural horizontal motion is at constant velocity unless a force acts:

More information

Solving Quadratic Equations

Solving Quadratic Equations 9.3 Solving Quadratic Equations by Using the Quadratic Formula 9.3 OBJECTIVES 1. Solve a quadratic equation by using the quadratic formula 2. Determine the nature of the solutions of a quadratic equation

More information

Steps to Solving Newtons Laws Problems.

Steps to Solving Newtons Laws Problems. Mathematical Analysis With Newtons Laws similar to projectiles (x y) isolation Steps to Solving Newtons Laws Problems. 1) FBD 2) Axis 3) Components 4) Fnet (x) (y) 5) Subs 1 Visual Samples F 4 1) F 3 F

More information

Chapter 8: Potential Energy and Conservation of Energy. Work and kinetic energy are energies of motion.

Chapter 8: Potential Energy and Conservation of Energy. Work and kinetic energy are energies of motion. Chapter 8: Potential Energy and Conservation of Energy Work and kinetic energy are energies of motion. Consider a vertical spring oscillating with mass m attached to one end. At the extreme ends of travel

More information

Weight The weight of an object is defined as the gravitational force acting on the object. Unit: Newton (N)

Weight The weight of an object is defined as the gravitational force acting on the object. Unit: Newton (N) Gravitational Field A gravitational field as a region in which an object experiences a force due to gravitational attraction Gravitational Field Strength The gravitational field strength at a point in

More information

Gravitational Potential Energy

Gravitational Potential Energy Gravitational Potential Energy Consider a ball falling from a height of y 0 =h to the floor at height y=0. A net force of gravity has been acting on the ball as it drops. So the total work done on the

More information

AP Physics 1 Midterm Exam Review

AP Physics 1 Midterm Exam Review AP Physics 1 Midterm Exam Review 1. The graph above shows the velocity v as a function of time t for an object moving in a straight line. Which of the following graphs shows the corresponding displacement

More information

Chapter 4. Forces and Newton s Laws of Motion. continued

Chapter 4. Forces and Newton s Laws of Motion. continued Chapter 4 Forces and Newton s Laws of Motion continued 4.9 Static and Kinetic Frictional Forces When an object is in contact with a surface forces can act on the objects. The component of this force acting

More information

LAB 6 - GRAVITATIONAL AND PASSIVE FORCES

LAB 6 - GRAVITATIONAL AND PASSIVE FORCES L06-1 Name Date Partners LAB 6 - GRAVITATIONAL AND PASSIVE FORCES OBJECTIVES And thus Nature will be very conformable to herself and very simple, performing all the great Motions of the heavenly Bodies

More information

Name per due date mail box

Name per due date mail box Name per due date mail box Rolling Momentum Lab (1 pt for complete header) Today in lab, we will be experimenting with momentum and measuring the actual force of impact due to momentum of several rolling

More information

Experiment 2: Conservation of Momentum

Experiment 2: Conservation of Momentum Experiment 2: Conservation of Momentum Learning Goals After you finish this lab, you will be able to: 1. Use Logger Pro to analyze video and calculate position, velocity, and acceleration. 2. Use the equations

More information

AP Physics Applying Forces

AP Physics Applying Forces AP Physics Applying Forces This section of your text will be very tedious, very tedious indeed. (The Physics Kahuna is just as sorry as he can be.) It s mostly just a bunch of complicated problems and

More information

Ch 8 Potential energy and Conservation of Energy. Question: 2, 3, 8, 9 Problems: 3, 9, 15, 21, 24, 25, 31, 32, 35, 41, 43, 47, 49, 53, 55, 63

Ch 8 Potential energy and Conservation of Energy. Question: 2, 3, 8, 9 Problems: 3, 9, 15, 21, 24, 25, 31, 32, 35, 41, 43, 47, 49, 53, 55, 63 Ch 8 Potential energ and Conservation of Energ Question: 2, 3, 8, 9 Problems: 3, 9, 15, 21, 24, 25, 31, 32, 35, 41, 43, 47, 49, 53, 55, 63 Potential energ Kinetic energ energ due to motion Potential energ

More information

8. Potential Energy and Conservation of Energy Potential Energy: When an object has potential to have work done on it, it is said to have potential

8. Potential Energy and Conservation of Energy Potential Energy: When an object has potential to have work done on it, it is said to have potential 8. Potential Energy and Conservation of Energy Potential Energy: When an object has potential to have work done on it, it is said to have potential energy, e.g. a ball in your hand has more potential energy

More information

Chapter 9. is gradually increased, does the center of mass shift toward or away from that particle or does it remain stationary.

Chapter 9. is gradually increased, does the center of mass shift toward or away from that particle or does it remain stationary. Chapter 9 9.2 Figure 9-37 shows a three particle system with masses m 1 3.0 kg, m 2 4.0 kg, and m 3 8.0 kg. The scales are set by x s 2.0 m and y s 2.0 m. What are (a) the x coordinate and (b) the y coordinate

More information