Chapter 6. Work and Energy


 Avice Hicks
 3 years ago
 Views:
Transcription
1 Chapter 6 Work and Energy
2 ENERGY IS THE ABILITY TO DO WORK = TO APPLY A FORCE OVER A DISTANCE= Example: push over a distance, pull over a distance. Mechanical energy comes into 2 forms: Kinetic energy KE or energy of motion. The kinetic energy changes if the speed changes. KE = 0.5 mv 2 Potential energy PE like the gravitational potential energy: PEg=mgh h is the height above the ground. PE is Stored energy. It depends on the position of The object. (height for example). You need to define a reference level for which the energy =PE=0. So a book on a table has potential energy. If it drops it can hurt. You also have elastic potential energy stored in a spring (stretched or Compressed). Ready to push or pull over a distance. The energy depends On the position of the spring when compressed or stretched relative to its equilibrium position. Note: fat is chemical potential energy. Ready to be burnt and transformed.
3 We will come back to energy in 6.3. But the point it to define the word WORK in Physics. It has a special meaning. WORK is done on a system by a force only if the effect of the force Is to speed up pr slow done the system. If the system is not moving When acted upon by the force, no work is done. If, because of the force, the speed of the system increases the WORK is positive. If the speed decreases, the WORK is negative. Note that more than 1 force can act on an object. So 1 force can speed up The object while another force slows it down (like friction/air resistance). In that case you need to find the net force to find the change in energy Of motion. Examples: 1.You push on a wall. Puffing, swearing, sweating. Are you doing work on the wall. (is your push is?) Ask is the energy of motion the wall increases? (did it move?) 2.You are lifting your computer from the table to the shelf. What are the 2 forces acting on the computer. Which one is doing a positive work? And a negative work?
4 You are pushing a cart. The cart moves as a consequence. Are you doing work on the car? Is it positive? The frictional force slows down cars. Is it doing work? Is it positive or negative? What about air resistance on a parachute? A drive engine on a plane? When work is done (positive or negative), A force F is applied over a Displacement x. Say you are carrying a suitcase around. Moving at a constant speed. The suitcase stays at the same level. Is the lifting force doing work? (perpendicular to the displacement). So always ask your self if the force under consideration (or one of the component of the force) is increasing the velocity of an object and in which direction.
5 Let's take the simple case: The force is along the xaxis and the displacement is also along the xaxis. How to compute the work W done on an object by the force F If the object moves by a distance s. What do you think? think Do you expect the work done to increase with the distance The object moves and with the force applied?
6 6.1 Work Done by a Constant Force W = 1 N m = Fs 1 joule ( J) THIS quantity W measured the amount of energy transferred from You to the car. It measured how many calories you burnt to push the car. Actually we are not a very efficient machine so most of the calories burnt Are lost to heat. 1 food calorie is 1 Cal is about 4,200 joules.
7 To find the work done by a force: I identify the displacement direction II Find the component of the force along the displacement. If the force is perpendicular to the displacement work=0 If there is no displacement work=0 Multiply the component by the displacement : Long the xaxis Fx(X) or along the yaxis Fy(Y) II If the force slows down the motion the work is negative. If the force speeds up the object, the work is positive.
8 6.1 Work Done by a Constant Force
9 W Consider this example above. The force has 2 components. 1 along the Xaxis and 1 along the yaxis. Which component is doinf The work? Which component is making the suitcase move? Fy FN Fx Along the Xaxis : Fx increases the velocity of the suitcase Fxfk = mass x acceleration Along the Yaxis Fy and Fn are balanced by W, no position change, no Increase in speed.
10 SO in that case: WORK done by F on the suitcase is: W by F = horizontal component of F x W by F = Fx (X) displacement X Note that the work done by Fx is positive The work done by the normal FN is (none) The work done by fk is (slows down the object) The work done by the weight is (none) The work done by Fy is (none) SO ONLY THE COMPONENT // DISPLACEMENT is doing work. so:  no displacement MEANS WORK=0 no transfer of energy  component perpendicular to displacement means WORK = 0
11 NET WORK DONE on an object = WORK done by the net force. For the suit case: NET FORCE = Fx fk NET WORK = (Fx fk) x displacement. Example: Find the net work done on the suitcase if the horizontal component of F is And the frictional force is and the displacement is 5m. This quantity is the increase of energy Of the suitcase. Amount of energy Transferred to the suitcase. We can compute its increase in speed. Its change in kinetic energy.
12 Easy examples First draw the the freebody diagram and identify the components That do the work.. Source: Physics of every day phenomena. Griffith. McGraw Hill 1. A woman does 160 J of work to move a table 4 m across the floor. What is the magnitude of the force that the woman applied to the table if this Force is applied in the horizontal direction? 2. A force of 60N used to push a chair across a room does 300J of work. How far does the chair move in this process? 3. A rope applies a horizontal force of 180N to pull a crate a distance of 2m Across the floor. A frictional force of 120N opposes this motion. A) What is the work applied by the rope. B)What is the work done by the frictional force. C)What is the total work done on the crate?
13 A force of 50N is used to drag a crate 4m across a floor. The force is directed at an angle upward from the crate so the vertical Component is 30N and the horizontal component is 40N. 50N 30N 40N 4m What is the work done by the horizontal component of the force? What is the work done by the vertical component of the force? What is the total work done?
14 6.1 Work Done by a Constant Force SO WORK done a force F on an object = Component of force along the displacement x displacement. Let's go back to the example of the suit case again. The object is moved only along the xaxis. So only the horizontal component of F is doing work. W = Fx (X) or
15 6.1 Work Done by a Constant Force W = ( F cosθ ) X cos0 = 1 cos90 = 0 cos180 = 1 Work is positive and max No work is done Work is negative and minimum
16 NET WORK = Sum of the work of the forces. NO net work = no increase in speed, no change in height, no stretching Of the spring In which one of the following situations is zero net work done? a) a bunch of bananas are placed on a spring scale in the supermarket Bananas are placed on a scale. The spring stretches. b) a sky diver falls from an airplane before opening her parachute Weight is doing work on the diver because the speed increases. (at a slower rate) c) a horse pulls a wagon at a constant velocity The horse is doing a positive work, but friction is doing a negative work such as they cancel each other. d) a snowball rolls down a hill Height is changing because 1 component of the weight is pulling along slope. e) a skateboarder steps on a skateboard and begins to roll When you start moving, speed increases
17 Work may be expressed using all of the following units except: a) watt b) joule c) N m d) erg e) ft lb
18 A 5.0kg ball on the end of a chain is whirled at a constant speed of 1.0 m/s in a horizontal circle of radius 3.0 m. What is the work done by the centripetal force during one revolution? a) 2.5 J b) 1.7 J c) 1.2 J d) 0.56 J e) zero J
19 Which one of the following combinations of units is equal to the joule? a) kg m 2 /s b) kg m c) kg m/s d) kg m 2 /s 2 e) kg s
20 In which one of the following circumstances does the force do positive work on the object? a) The direction of the force is perpendicular to the object s displacement. b) The direction of the force is in the opposite direction to the object s displacement. c) No matter the direction of the force, positive work will be done if there is a displacement of the object. d) The direction of the force is in the same direction as the object s displacement. e) The object s displacement is zero meters as the force is applied.
21 REMEMBER: If no displacement = no work If force (or component of a force) is perpendicular to displacement = no work Work measures the transfer of energy from 1 system to another.
22 6.1 Work Done by a Constant Force Example 1 Pulling a SuitcaseonWheels Find the work done if the force is 45.0N, the angle is 50.0 degrees, and the displacement is 75.0 m.
23 W = ( ) [ F cosθ s = ( 45.0 N) cos 50.0 ]( 75.0 m) = 2170 J
24 6.1 Work Done by a Constant Force The weight lifter is benchpressing a barbell. The weight of the barbell is 710N. He raises the barbell a distance 0f 0.65m Then he lowers the barbell in the same direction Work is done on if the energy of the barbell increases. Find the work done in each case. It can be 0, positive or negative. Convert to Kcal (1 kcal = 1 food cal = 4,200 joules.
25 6.1 Work Done by a Constant Force W = 0 W = 460J W = 460J 460J= 0.1 Kcal You have to lift and lower 2000 times to lose 1 soda can (about 220Kcal)!!!!
26 6.1 Work Done by a Constant Force Example 3 Accelerating a Crate The truck is accelerating at a rate of m/s 2. The mass of the crate is 120kg and it does not slip. The magnitude of the displacement is 65 m. Newton's first law says, a mass stays at rest unless acted upon By a force. How come the crate does not slip? It should according to inertia's principle? First do the freebody diagram for the crate.
27 6.1 Work Done by a Constant Force Example 3 Accelerating a Crate The truck is accelerating at a rate of m/s 2. The mass of the crate is 120kg and it does not slip. The magnitude of the displacement is 65 m. Find the net force acting on the crate. What is the total work done on the crate by all of the forces acting on it?
28 6.1 Work Done by a Constant Force The angle between the displacement and the friction force is 0 degrees. f s = ma = ( )( kg 1.5m s ) = 180N W = [( ) ]( ) 4 180N cos0 65 m = J
29 Assignments with work: 1. A. motorist runs out of gas on a level road 200m from a gas station. The driver Pushed the 1,200kg car to the station. If a 150N force is required to keep the car Moving, how much work does the driver do? 2. p.188 number 1. You need to focus on the skier and draw forces doing work In a freebody diagram. Find the work done by the tension in the rope.use a top view. (source: Johnson and Cutnell, Wiley Physics 8e) Hint: first you need to find The displacement covered in 12s. Speed is constant = 9.30 m/s X Then you need to do find the component Of thetension (135N) that is doing the Work. (responsible for keeping The skier moving). Note: negative work is done by the Friction between the water and the ski. Net work =0 since there is no increase In speed.
30 3.number 3 p.188. Work is negative when the force oppose the increase in energy, That is decrease the energy. 4. number 4 p.188 same idea as in number 5 p.188 let's go back to the suit case. The angle is unknown. The magnitude of F is 30N, the distance covered is 50m The work done by the horizontal component of F is 1,100 J. Find the angle.
31 6. number 6 p.188. Like for the suit case example. In (b) F has no component along the vertical/. 7. number 8 p N F 29 (a) remember since the cart is moving At a constant speed that means: Left = right or friction = Fx 48=Fcos(29) solve for F (b) work done by Fx (d=22m) work done by fk (d) work done by the weight
32 8.Number7 p.188. VERY GOOD EXAMPLE TO DEVELOP STRATEGY (a) what make more sense to you? (b)follow steps: Only the xcomponent of The thrust and the xcomponent of the weight are doing Work. I.First for each case find the xcomponents of F and W (see below) II.Find the work done by each component for each case. (work <0 when opposes motion) III. Find the net work for each case. IV. Find the difference. 25 case1 Wx=  Tx= Work done by Wx= Work done by T = Net work = Case2!!angle between W and yaxis is 25 Wx=  Tx= Work done by Wx= Work done by T = Net work = Find the difference. You don't need to know T, since you are computing the difference, the work done by T will cancel.
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 informationChapter 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 informationChapter 6. Work and Energy
Chapter 6 Work and Energy The concept of forces acting on a mass (one object) is intimately related to the concept of ENERGY production or storage. A mass accelerated to a nonzero speed carries energy
More informationWork Energy & Power. September 2000 Number 05. 1. Work If a force acts on a body and causes it to move, then the force is doing work.
PhysicsFactsheet September 2000 Number 05 Work Energy & Power 1. Work If a force acts on a body and causes it to move, then the force is doing work. W = Fs W = work done (J) F = force applied (N) s = distance
More information9. 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 informationC 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 informationHW Set II page 1 of 9 PHYSICS 1401 (1) homework solutions
HW Set II page 1 of 9 450 When a large star becomes a supernova, its core may be compressed so tightly that it becomes a neutron star, with a radius of about 20 km (about the size of the San Francisco
More informationWork, Energy and Power Practice Test 1
Name: ate: 1. How much work is required to lift a 2kilogram mass to a height of 10 meters?. 5 joules. 20 joules. 100 joules. 200 joules 5. ar and car of equal mass travel up a hill. ar moves up the hill
More informationWORKSHEET: KINETIC AND POTENTIAL ENERGY PROBLEMS
WORKSHEET: KINETIC AND POTENTIAL ENERGY PROBLEMS 1. Stored energy or energy due to position is known as Potential energy. 2. The formula for calculating potential energy is mgh. 3. The three factors that
More informationPhysics 125 Practice Exam #3 Chapters 67 Professor Siegel
Physics 125 Practice Exam #3 Chapters 67 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 informationVELOCITY, ACCELERATION, FORCE
VELOCITY, ACCELERATION, FORCE velocity Velocity v is a vector, with units of meters per second ( m s ). Velocity indicates the rate of change of the object s position ( r ); i.e., velocity tells you how
More informationName Period WORKSHEET: KINETIC AND POTENTIAL ENERGY PROBLEMS. 1. Stored energy or energy due to position is known as energy.
Name Period Date WORKSHEET: KINETIC AND POTENTIAL ENERGY PROBLEMS 1. Stored energy or energy due to position is known as energy. 2. The formula for calculating potential energy is. 3. The three factors
More informationWork. Work = Force x parallel distance (parallel component of displacement) F v
Work Work = orce x parallel distance (parallel component of displacement) W k = d parallel d parallel Units: N m= J = " joules" = ( kg m2/ s2) = average force computed over the distance r r When is not
More informationCh 7 Kinetic Energy and Work. Question: 7 Problems: 3, 7, 11, 17, 23, 27, 35, 37, 41, 43
Ch 7 Kinetic Energy and Work Question: 7 Problems: 3, 7, 11, 17, 23, 27, 35, 37, 41, 43 Technical definition of energy a scalar quantity that is associated with that state of one or more objects The state
More informationPhysics 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 informationKE =? v o. Page 1 of 12
Page 1 of 12 CTEnergy1. 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 informationPHY231 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 informationCHAPTER 6 WORK AND ENERGY
CHAPTER 6 WORK AND ENERGY CONCEPTUAL QUESTIONS. REASONING AND SOLUTION The work done by F in moving the box through a displacement s is W = ( F cos 0 ) s= Fs. The work done by F is W = ( F cos θ). s From
More informationWeight 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 informationPHY231 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 informationGravitational 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 informationWORK 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 Newtonmeter (Nm) = Joule, J If you exert a force of
More informationwww.mathsbox.org.uk Displacement (x) Velocity (v) Acceleration (a) x = f(t) differentiate v = dx Acceleration Velocity (v) Displacement x
Mechanics 2 : Revision Notes 1. Kinematics and variable acceleration Displacement (x) Velocity (v) Acceleration (a) x = f(t) differentiate v = dx differentiate a = dv = d2 x dt dt dt 2 Acceleration Velocity
More informationWork, Power, Energy Multiple Choice. PSI Physics. Multiple Choice Questions
Work, Power, Energy Multiple Choice PSI Physics Name Multiple Choice Questions 1. A block of mass m is pulled over a distance d by an applied force F which is directed in parallel to the displacement.
More informationPhysics 201 Homework 8
Physics 201 Homework 8 Feb 27, 2013 1. A ceiling fan is turned on and a net torque of 1.8 Nm is applied to the blades. 8.2 rad/s 2 The blades have a total moment of inertia of 0.22 kgm 2. What is the
More informationv 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 informationPhysics 11 Assignment KEY Dynamics Chapters 4 & 5
Physics Assignment KEY Dynamics Chapters 4 & 5 ote: for all dynamics problemsolving questions, draw appropriate free body diagrams and use the aforementioned problemsolving method.. Define the following
More informationphysics 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 informationName: Partners: Period: Coaster Option: 1. In the space below, make a sketch of your roller coaster.
1. In the space below, make a sketch of your roller coaster. 2. On your sketch, label different areas of acceleration. Put a next to an area of negative acceleration, a + next to an area of positive acceleration,
More informationConceptual Questions: Forces and Newton s Laws
Conceptual Questions: Forces and Newton s Laws 1. An object can have motion only if a net force acts on it. his statement is a. true b. false 2. And the reason for this (refer to previous question) is
More informationB) 286 m C) 325 m D) 367 m Answer: B
Practice Midterm 1 1) When a parachutist jumps from an airplane, he eventually reaches a constant speed, called the terminal velocity. This means that A) the acceleration is equal to g. B) the force of
More information3 Work, Power and Energy
3 Work, Power and Energy At the end of this section you should be able to: a. describe potential energy as energy due to position and derive potential energy as mgh b. describe kinetic energy as energy
More information5. Forces and MotionI. Force is an interaction that causes the acceleration of a body. A vector quantity.
5. Forces and MotionI 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 informationWork, Energy and Power
Work, Energy and Power In this section of the Transport unit, we will look at the energy changes that take place when a force acts upon an object. Energy can t be created or destroyed, it can only be changed
More informationAt 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 informationSerway_ISM_V1 1 Chapter 4
Serway_ISM_V1 1 Chapter 4 ANSWERS TO MULTIPLE CHOICE QUESTIONS 1. Newton s second law gives the net force acting on the crate as This gives the kinetic friction force as, so choice (a) is correct. 2. As
More informationChapter 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 informationChapter 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 informationChapter 7 WORK, ENERGY, AND Power Work Done by a Constant Force Kinetic Energy and the WorkEnergy Theorem Work Done by a Variable Force Power
Chapter 7 WORK, ENERGY, AND Power Work Done by a Constant Force Kinetic Energy and the WorkEnergy Theorem Work Done by a Variable Force Power Examples of work. (a) The work done by the force F on this
More informationChapter 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 informationW i f(x i ) x. i=1. f(x i ) x = i=1
Work Force If an object is moving in a straight line with position function s(t), then the force F on the object at time t is the product of the mass of the object times its acceleration. F = m d2 s dt
More informationPhysics: 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 buckleup? A) the first law
More informationSteps 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 informationAP 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 informationPHY121 #8 Midterm I 3.06.2013
PHY11 #8 Midterm I 3.06.013 AP Physics Newton s Laws AP Exam Multiple Choice Questions #1 #4 1. When the frictionless system shown above is accelerated by an applied force of magnitude F, the tension
More informationWork, 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 1.5kg psychology textbook out of a second floor classroom window until her arm is tired; then she releases
More informationWorkEnergy Bar Charts
Name: WorkEnergy Bar Charts Read from Lesson 2 of the Work, Energy and Power chapter at The Physics Classroom: http://www.physicsclassroom.com/class/energy/u5l2c.html MOP Connection: Work and Energy:
More information10.1 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 informationCurso20122013 Física Básica Experimental I Cuestiones Tema IV. Trabajo y energía.
1. A body of mass m slides a distance d along a horizontal surface. How much work is done by gravity? A) mgd B) zero C) mgd D) One cannot tell from the given information. E) None of these is correct. 2.
More informationF 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 250N force is directed horizontally as shown to push a 29kg box up an inclined plane at a constant speed. Determine the magnitude of the normal force,
More informationCh 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 informationLeaPS Workshop March 12, 2010 Morehead Conference Center Morehead, KY
LeaPS Workshop March 12, 2010 Morehead Conference Center Morehead, KY Word Bank: Acceleration, mass, inertia, weight, gravity, work, heat, kinetic energy, potential energy, closed systems, open systems,
More informationUnit 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 informationPhysics Midterm Review Packet January 2010
Physics Midterm Review Packet January 2010 This Packet is a Study Guide, not a replacement for studying from your notes, tests, quizzes, and textbook. Midterm Date: Thursday, January 28 th 8:1510:15 Room:
More informationFRICTION, WORK, AND THE INCLINED PLANE
FRICTION, WORK, AND THE INCLINED PLANE Objective: To measure the coefficient of static and inetic friction between a bloc and an inclined plane and to examine the relationship between the plane s angle
More informationNewton 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 informationAP Physics  Chapter 8 Practice Test
AP Physics  Chapter 8 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1. A single conservative force F x = (6.0x 12) N (x is in m) acts on
More informationPHYS 211 FINAL FALL 2004 Form A
1. Two boys with masses of 40 kg and 60 kg are holding onto either end of a 10 m long massless pole which is initially at rest and floating in still water. They pull themselves along the pole toward each
More informationPhysics 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 informationMULTIPLE 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 informationWorksheet #1 Free Body or Force diagrams
Worksheet #1 Free Body or Force diagrams Drawing FreeBody Diagrams Freebody diagrams are diagrams used to show the relative magnitude and direction of all forces acting upon an object in a given situation.
More informationSolution Derivations for Capa #11
Solution Derivations for Capa #11 1) A horizontal circular platform (M = 128.1 kg, r = 3.11 m) rotates about a frictionless vertical axle. A student (m = 68.3 kg) walks slowly from the rim of the platform
More informationPHYSICS 111 HOMEWORK SOLUTION, week 4, chapter 5, sec 17. February 13, 2013
PHYSICS 111 HOMEWORK SOLUTION, week 4, chapter 5, sec 17 February 13, 2013 0.1 A 2.00kg object undergoes an acceleration given by a = (6.00î + 4.00ĵ)m/s 2 a) Find the resultatnt force acting on the object
More information1. Mass, Force and Gravity
STE Physics Intro Name 1. Mass, Force and Gravity Before attempting to understand force, we need to look at mass and acceleration. a) What does mass measure? The quantity of matter(atoms) b) What is the
More informationBHS 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 (15641642): 1 st true scientist and 1 st person to use
More informationChapter 5 Using Newton s Laws: Friction, Circular Motion, Drag Forces. Copyright 2009 Pearson Education, Inc.
Chapter 5 Using Newton s Laws: Friction, Circular Motion, Drag Forces Units of Chapter 5 Applications of Newton s Laws Involving Friction Uniform Circular Motion Kinematics Dynamics of Uniform Circular
More informationResistance in the Mechanical System. Overview
Overview 1. What is resistance? A force that opposes motion 2. In the mechanical system, what are two common forms of resistance? friction and drag 3. What is friction? resistance that is produced when
More informationChapter 07 Test A. Name: Class: Date: Multiple Choice Identify the choice that best completes the statement or answers the question.
Class: Date: Chapter 07 Test A Multiple Choice Identify the choice that best completes the statement or answers the question. 1. An example of a vector quantity is: a. temperature. b. length. c. velocity.
More informationWork, Energy, Conservation of Energy
This test covers Work, echanical energy, kinetic energy, potential energy (gravitational and elastic), Hooke s Law, Conservation of Energy, heat energy, conservative and nonconservative forces, with soe
More informationAcceleration due to Gravity
Acceleration due to Gravity 1 Object To determine the acceleration due to gravity by different methods. 2 Apparatus Balance, ball bearing, clamps, electric timers, meter stick, paper strips, precision
More informationAP1 Oscillations. 1. Which of the following statements about a springblock oscillator in simple harmonic motion about its equilibrium point is false?
1. Which of the following statements about a springblock oscillator in simple harmonic motion about its equilibrium point is false? (A) The displacement is directly related to the acceleration. (B) The
More informationObjective: Equilibrium Applications of Newton s Laws of Motion I
Type: Single Date: Objective: Equilibrium Applications of Newton s Laws of Motion I Homework: Assignment (111) Read (4.14.5, 4.8, 4.11); Do PROB # s (46, 47, 52, 58) Ch. 4 AP Physics B Mr. Mirro Equilibrium,
More informationB Answer: neither of these. Mass A is accelerating, so the net force on A must be nonzero Likewise for mass B.
CTA1. An Atwood's machine is a pulley with two masses connected by a string as shown. The mass of object A, m A, is twice the mass of object B, m B. The tension T in the string on the left, above mass
More informationLecture 6. Weight. Tension. Normal Force. Static Friction. Cutnell+Johnson: 4.84.12, second half of section 4.7
Lecture 6 Weight Tension Normal Force Static Friction Cutnell+Johnson: 4.84.12, second half of section 4.7 In this lecture, I m going to discuss four different kinds of forces: weight, tension, the normal
More informationWork and Conservation of Energy
Work and Conservation of Energy Topics Covered: 1. The definition of work in physics. 2. The concept of potential energy 3. The concept of kinetic energy 4. Conservation of Energy General Remarks: Two
More informationLecture 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 informationThe Big Idea. Key Concepts
The Big Idea Acceleration is caused by force. All forces come in pairs because they arise in the interaction of two objects you can t hit without being hit back! The more force applied, the greater the
More informationENERGYand WORK (PART I and II) 9MAC
ENERGYand WORK (PART I and II) 9MAC Purpose: To understand work, potential energy, & kinetic energy. To understand conservation of energy and how energy is converted from one form to the other. Apparatus:
More informationTennessee 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 Fgrade. Other instructions will be given in the Hall. MULTIPLE CHOICE.
More informationProblem 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 informationL9 Conservation of Energy, Friction and Circular Motion. Kinetic energy. conservation of energy. Potential energy. Up and down the track
L9 Conseration of Energy, Friction and Circular Motion Kinetic energy, potential energy and conseration of energy What is friction and what determines how big it is? Friction is what keeps our cars moing
More informationObjective: Work Done by a Variable Force Work Done by a Spring. Homework: Assignment (125) Do PROBS # (64, 65) Ch. 6, + Do AP 1986 # 2 (handout)
Double Date: Objective: Work Done by a Variable Force Work Done by a Spring Homework: Assignment (125) Do PROBS # (64, 65) Ch. 6, + Do AP 1986 # 2 (handout) AP Physics B Mr. Mirro Work Done by a Variable
More informationEnergy  Key Vocabulary
Energy  Key Vocabulary Term Potential Energy Kinetic Energy Joules Gravity Definition The energy an object possesses due to its position. PE = mgh The energy an object possesses when it is in motion.
More informationTEACHER ANSWER KEY November 12, 2003. Phys  Vectors 11132003
Phys  Vectors 11132003 TEACHER ANSWER KEY November 12, 2003 5 1. A 1.5kilogram lab cart is accelerated uniformly from rest to a speed of 2.0 meters per second in 0.50 second. What is the magnitude
More information2 Newton s First Law of Motion Inertia
2 Newton s First Law of Motion Inertia Conceptual Physics Instructor Manual, 11 th Edition SOLUTIONS TO CHAPTER 2 RANKING 1. C, B, A 2. C, A, B, D 3. a. B, A, C, D b. B, A, C, D 4. a. A=B=C (no force)
More informationwhile the force of kinetic friction is fk = µ
19. REASONING AND SOLUION We know that µ s =2.0µ k for a crate in contact with a MAX cement floor. he maximum force of static friction is fs = µ sfn while the force of kinetic friction is fk = µ kfn. As
More informationNEWTON 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 informationReview 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 informationAP1 Dynamics. Answer: (D) foot applies 200 newton force to nose; nose applies an equal force to the foot. Basic application of Newton s 3rd Law.
1. A mixed martial artist kicks his opponent in the nose with a force of 200 newtons. Identify the actionreaction force pairs in this interchange. (A) foot applies 200 newton force to nose; nose applies
More informationWork, Energy and Power
Name: KEY Work, Energy and Power Objectives: 1. To understand work and its relation to energy. 2. To understand how energy can be transformed from one form into another. 3. To compute the power from the
More informationPhysics 111: Lecture 4: Chapter 4  Forces and Newton s Laws of Motion. Physics is about forces and how the world around us reacts to these forces.
Physics 111: Lecture 4: Chapter 4  Forces and Newton s Laws of Motion Physics is about forces and how the world around us reacts to these forces. Whats a force? Contact and noncontact forces. Whats a
More informationLecture 7 Force and Motion. Practice with Freebody Diagrams and Newton s Laws
Lecture 7 Force and Motion Practice with Freebody Diagrams and Newton s Laws oday we ll just work through as many examples as we can utilizing Newton s Laws and freebody diagrams. Example 1: An eleator
More informationMidterm 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 information8. 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 informationAP 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 informationPractice Test SHM with Answers
Practice Test SHM with Answers MPC 1) If we double the frequency of a system undergoing simple harmonic motion, which of the following statements about that system are true? (There could be more than one
More informationPhysics. Lesson Plan #6 Forces David V. Fansler Beddingfield High School
Physics Lesson Plan #6 Forces David V. Fansler Beddingfield High School Force and Motion Objective Define a force and differentiate between contact forces and longrange forces; Recognize the significance
More informationChapter 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 informationWork, Power, and Energy: Explaining the causes of motion without Newton. KIN335 Spring 2005
Work, Power, and Energy: Explaining the causes of motion without Newton KIN335 Spring 2005 What you should know Definition of work and its characteristics Definition of energy (including kinetic energy
More information