PHYS Brooks Chapters 1 11

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1 PHYS Brooks Chapters 1 11 Select the response that best answers the given statement. Be sure to write all final multiple choice answers on your Scantron answer sheet. Problem: 1 A clown is shot straight up out of a cannon. The graph of his velocity versus time is shown. Determine the clown's vertical displacement from the instant he is shot out of the cannon at 0.0 seconds until when he reaches zero velocity at 2.5 seconds. a. 25 m b. 31 m c. 42 m d. 63 m Problem: 2 A dust mote moves along a line. Its position is described by the function x(t) = 12-30t - 6t 2 where position is in meters and time is in seconds. What is the mote's instantaneous acceleration at t = 7 s? Express your answer to the nearest integer. a m/s 2 b m/s 2 c m/s 2 d m/s 2 Problem: 3 A Honda and a Porsche race, starting from the same point. The Honda accelerates at a constant 4.00 m/s 2 ; the Porsche at a constant 8.00 m/s 2. The Porsche gives the Honda an advantage by letting it start first. The Honda accelerates, and when it is traveling at 23.0 m/s, the Porsche starts. How far do the cars travel from the starting point before the Porsche catches up with the Honda? a. 92 m b. 387 m c. 773 m d m Problem: 4 A person throws a ball straight up. He releases the ball at a height of 1.75 m above the ground and with a velocity of 12.0 m/s. Ignore the effects of air resistance. How high above the ground does the ball go? a m b m c m d m

2 Problem: 5 A cannon mounted on a pirate ship fires a cannonball at 125 m/s horizontally, at a height of 17.5 m above the ocean surface. Ignore air resistance. How far from the ship does it land? a. 156 m b. 236 m c. 267 m d m Problem: 6 You are returning a tennis ball that your five-year-old neighbor has accidentally thrown into your yard, but you need to throw it over a 3.0 m fence. You want to throw it so that it barely clears the fence. You are standing 0.50 m away from the fence and throw underhanded, releasing the ball at a height of 1.0 m. State the initial velocity vector you would use to accomplish this. a. (0.78, 6.3) m/s b. (0.65, 8.3) m/s c. (0.46, 4.2) m/s d. (0.22, 13) m/s Problem: 7 A kg frozen hamburger patty has two forces acting on it that determine its horizontal motion. A 2.30 N force pushes it to the left, and a N force pushes it to the right. Taking right to be positive, what is its acceleration? a m/s 2 b m/s 2 c m/s 2 d m/s 2 Problem: 8 A 75.0 kg man sits on a massless cart that is on a horizontal surface. The cart is initially stationary and it can move without friction or air resistance. The man throws a 5.00 kg stone in the positive direction, applying a force to it so that it has acceleration m/s 2 as measured by a nearby observer on the ground. What is the man's acceleration during the throw, as seen by the same observer? a m/s 2 b m/s 2 c m/s 2 d m/s 2 Problem: 9 A firefighter whose weight is 812 N is sliding down a vertical pole, her speed increasing at the rate of 1.45 m/s 2. Gravity and friction are the two significant forces acting on her. What is the magnitude of the frictional force? a. 812 N b. 767 N c. 711 N d. 692 N Problem: 10 Consider a large spring, hanging vertically, with spring constant k = 3220 N/m. If the spring is stretched 25.0 cm from equilibrium and a block is attached to the end, the block stays still, neither accelerating upward nor downward. What is the mass of the block? a kg b kg c kg d kg

3 Problem: 11 A child sits still on a swing that is supported by two chains. Each chain makes a 15.0 angle with the vertical. The child's mass is 25.0 kg. What is the tension in each chain? (Ignore the mass of the seat and chains.) a. 156 N b. 127 N c N d N Problem: 12 A block of mass 15.0 kg sits on a plane that is inclined at a 37.0 angle to the horizontal. A 227 N force, pointing up the plane, is applied to the block. The coefficient of kinetic friction is What is the speed of the block after 2.00 s? a m/s b m/s c m/s d m/s Problem: 13 A climber of mass 64.8 kg is rappelling down a cliff, but has momentarily paused. She stands with her feet pressed against the icy, frictionless rock face and her body horizontal. A rope of negligible mass is attached to her near her waist, 1.04 m horizontally from the rock face. There is 5.25 m of rope between her waist and where the rope is attached to a chock in the face of the vertical wall she is descending. Calculate the tension in the rope. a. 235 N b. 456 N c. 648 N d. 876 N Problem: 14 A horizontal net force of 75.5 N is exerted on a 47.2 kg sofa, causing it to slide 2.40 meters along the ground. How much work does the force do? a. 113 J b. 181 J c. 254 J d J Problem: 15 Find the dot product of (2, 3) and (4, -7). a. -2 b. 8 c. -13 d. 29

4 Problem: 16 A force applied to a tennis ball is described by the function F(x) = 2.00x , with the force in newtons and the position in meters. How much work does it do on a tennis ball as it moves from m to a new position at 3.00 m? a J b J c J d J Problem: 17 You are about to shoot two identical cannonballs straight up into the air. The first cannonball has 4.0 times as much initial velocity as the second. How many times higher will the first cannonball go compared to the second? a. 16 times higher b. 8 times higher c. 4 times higher d. It will achieve the same height Problem: 18 How much work does a 5.00 horsepower outboard motor do in one minute? State your answer in joules. a. 2.24e+5 J b. 1.56e+5 J c. 9.65e+4 J d. 2.89e+3 J Problem: 19 When your sled starts down from the top of a hill, it hits a frictionless ice slick that extends all the way down the hill. At the bottom, the ground is dry and level. The effective coefficient of friction between the sled runners and the ground is If the hill is 50 m high, how far will your sled travel once it reaches the bottom? a. 12 m b. 45 m c. 81 m d. 160 m Problem: 20 A baseball arrives at home plate at a speed of 43.3 m/s. The batter hits the ball along the same line straight back to the pitcher at 68.4 m/s. The baseball has a mass of kg and the bat is in contact with the ball for 6.28e-4 s. What is the magnitude of the average force on the ball from the bat? a N b N c N d N Problem: 21 A particle moves along the z-axis, pushed by a net force that is time-dependent and given by Fz(t) = 3.00t t 3, where the force is in newtons and the time is in seconds. Between t = 0 and t = 4.00 seconds, what is the particle's change in momentum? a. 113 kg m/s b. 152 kg m/s c. 175 kg m/s d. 560 kg m/s Problem: 22 A rifle fires a bullet of mass kg which leaves the barrel with a positive velocity of 304 m/s. The mass of the rifle and bullet is 3.31 kg. At what velocity does the rifle recoil? a m/s b m/s c m/s d m/s

5 Problem: 23 Ball A has mass 5.0 kg and is moving at -3.2 m/s when it strikes stationary ball B, which has mass 3.9 kg, in a head-on collision. If the collision is elastic, what is the velocity of ball A after the collision? a m/s b m/s c m/s d m/s Problem: 24 A 1.30 kg book is resting on a horizontal surface. A large kg spitball slides horizontally and sticks to the book. The book moves m before coming to a rest. If the coefficient of kinetic friction between the book and the surface is 0.670, what was the speed of the spitball when it struck the book? a m/s b m/s c m/s d m/s Problem: 25 Given A = 2i - 3k, B = 5k determine the angle between A and B? a. 30 o b. 27 o c. 56 o d. 34 o Problem: 26 When tires are installed or reinstalled on a car, they are usually first balanced on a device that spins them to see if they wobble. A tire with a radius of m is rotated on a tire balancing device at exactly 460 revolutions per minute. A small stone is embedded in the tread of the tire. What is the magnitude of the centripetal acceleration experienced by the stone? a. 105 m/s 2 b. 654 m/s 2 c. 752 m/s 2 d. 882 m/s 2 Problem: 27 Fifteen clowns are late to a party. They jump into their sporty coupe and start driving. Eventually they come to a level curve, with a radius of 29.5 meters. What is the top speed at which they can drive successfully around the curve? The coefficient of static friction between the car's tires and the road is a m/s b m/s c m/s d m/s Problem: 28 The blades of a kitchen blender rotate counterclockwise at 2.2e4 rpm (revolutions per minute) at top speed. It takes the blender 2.1 seconds to reach this top speed after being turned on. What is the average angular acceleration of the blades? a. 8.0e3 rad/s 2 b. 4.6e3 rad/s 2 c. 1.9e3 rad/s 2 d. 1.1e3 rad/s 2

6 Problem: 29 A cyclist starts from rest and rides in a straight line, increasing speed so that her wheels have a constant angular acceleration of 2.0 rad/s 2 around their axles. She accelerates until her wheels are rotating at 8.0 rad/s. If the radius of a tire is 0.31 meters, how far has the cyclist traveled? a. 2.5 m b. 3.0 m c. 5.0 m d. 7.5 m Problem: 30 A car starts a race from rest on a circular track and has a tangential speed of 43 m/s at the end of the third lap. The track has a radius of 91 m. If it has constant angular acceleration, what is the magnitude of its tangential acceleration? a m/s 2 b m/s 2 c m/s 2 d m/s 2 Problem: 31 Bob and Ray push on a door from opposite sides. They both push perpendicular to the door. Bob pushes 0.63 m from the door hinge with a force of 89 N. Ray pushes 0.57 m from the door hinge with a force of 98 N, in a manner that tends to turn the door in a clockwise direction. What is the net torque on the door? a N m b N m c N m d N m Problem: 32 Find the torque in rectangular notation for a force F = i + k that is applied at position r = 2i - 3k. The force is given in newtons and the position is given in meters. a. (3, -2, 5) N m b. (-5, -3, 0) N m c. (2, -5, 3) N m d. (0, -5, 0) N m Problem: 33 A large rectangular bank vault door, 2.20 m wide, is hinged on one edge. To close the door, the bank manager applies a constant force of 161 N at the opposite edge of the door, perpendicular to the door. If the door moves through an angle of 135 as it closes, how much work does the bank manager do on the door? a. 835 J b. 756 J c. 546 J d. 115 J Problem: 34 A thin rod 2.60 m long with mass 3.80 kg is rotated counterclockwise about an axis through its midpoint. It completes 3.70 revolutions every second. What is the magnitude of its angular momentum? a kg m 2 /s b kg m 2 /s c kg m 2 /s d kg m 2 /s

7 Problem: 35 A string is wound around the edge of a solid 1.60 kg disk with a m radius. The disk is initially at rest when the string is pulled, applying a force of 5.75 N in the plane of the disk and tangent to its edge. If the force is applied for 1.90 seconds, what is the magnitude of its final angular velocity? a. 185 rad/s b. 118 rad/s c. 105 rad/s d rad/s

8 Answers 1. B 2. B 3. C 4. A 5. B 6. A 7. A 8. A 9. D 10. A 11. B 12. A 13. C 14. B 15. C 16. A 17. A 18. A 19. C 20. A 21. B 22. B 23. D 24. A 25. D 26. D 27. D 28. D 29. C 30. A 31. D 32. D 33. A 34. A 35. C

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10 METRIC PREFIXES Prefix: Symbol: Magnitude: Yotta- Y Zetta- Z Exa- E Peta- P Tera- T Giga- G 10 9 Mega- M 10 6 myria- my 10 4 kilo- k 10 3 hecto- h 10 2 deka- da 10 Prefix: Symbol: Magnitude: deci- d 10-1 centi- c 10-2 milli- m 10-3 micro nano- n 10-9 pico- p femto- f atto- a zepto- z yocto- y 10-24