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#### Conceptual Physics 12th Ed by Paul G. Hewitt -Test Bank

*Conceptual Physics, 12e*** (Hewitt)****Chapter 6 Momentum**** **6.1 Multiple-Choice Questions 1) Which has the greater momentum when moving?

- A) a container ship
- B) a bullet
- C) either of these depending on speed

Answer: CDiff: 1Topic: Momentum 2) Which of the following has the largest momentum relative to Earth’s surface?

- A) a tightrope walker crossing Niagara Falls
- B) a pickup truck speeding along a highway
- C) a Mack truck parked in a parking lot
- D) the Science building on campus
- E) a mouse running across your room

Answer: BDiff: 1Topic: Momentum 3) A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is

- A) zero.
- B) twice.
- C) four times as much.
- D) unchanged.

Answer: BDiff: 1Topic: Momentum 4) A same-size iron ball and wooden ball are dropped simultaneously from a tower and reach the ground at the same time. The iron ball has a greater

- A) speed.
- B) acceleration.
- C) momentum.
- D) all of the above
- E) none of the above

Answer: CDiff: 1Topic: Momentum 5) The speed of a 4-kg ball with a momentum of 12 kg m/s is

- A) 3 m/s.
- B) 4 m/s.
- C) 12 m/s.
- D) 48 m/s.
- E) none of the above

Answer: ADiff: 2Topic: Momentum 6) The mass of a ball moving at 3 m/s with a momentum of 48 kg m/s is

- A) 4 kg.
- B) 12 kg.
- C) 16 kg.
- D) 144 kg.
- E) none of these

Answer: CDiff: 2Topic: Momentum 7) A large heavy truck and a small baby carriage roll down a hill. Neglecting friction, at the bottom of the hill, the baby carriage will likely have

- A) less momentum.
- B) about the same momentum.
- C) more momentum.

Answer: ADiff: 2Topic: Momentum 8) The total momentum of a flock of identical birds could be zero only if the birds are

- A) taking off from the ground.
- B) flying in the same direction.
- C) flying in different directions.
- D) very tired and coming down to rest.

Answer: CDiff: 2Topic: Momentum 9) If several balls are thrown straight up with different initial speeds, the quantity that will have the same value along their paths is their

- A) initial momentum.
- B) maximum height.
- C) time of travel.
- D) acceleration.
- E) none of the above

Answer: DDiff: 2Topic: Momentum10) A motorcycle of mass 100 kilograms slowly rolls off the edge of a cliff and falls for three seconds before reaching the bottom of a gully. Its momentum upon hitting the ground is

- A) 1,000 kg m/s.
- B) 2,000 kg m/s.
- C) 3,000 kg m/s.
- D) 4,000 kg m/s.
- E) 9,000 kg m/.

Answer: CDiff: 3Topic: Momentum 11) It is correct to say that impulse is equal to

- A) momentum.
- B) a corresponding change in momentum.
- C) force multiplied by the distance it acts.
- D) velocity multiplied by time.

Answer: BDiff: 1Topic: Impulse Changes Momentum 12) The impulse-momentum relationship is a direct result of

- A) Newton’s 1st law.
- B) Newton’s 2nd law.
- C) Newton’s 3rd law.
- D) Newton’s law of gravity.

Answer: BDiff: 1Topic: Impulse Changes Momentum 13) A car traveling along the highway brakes to a stop over a certain distance. More braking force is required if the car has

- A) more mass.
- B) more momentum.
- C) less stopping distance.
- D) all of the above
- E) none of the above

Answer: DDiff: 2Topic: Impulse 14) Padded dashboards in cars are safer in an accident than non-padded ones because passengers hitting the dashboard encounter

- A) lengthened time of contact.
- B) shorter time of contact.
- C) decreased impulse.
- D) increased momentum.

Answer: ADiff: 2Topic: Impulse15) The force on a dropped apple hitting the ground depends upon

- A) the speed of the apple just before it hits.
- B) the time of contact with the ground.
- C) whether or not the apple bounces.
- D) all of the above

Answer: DDiff: 2Topic: Impulse 16) When Peter tosses an egg against a sagging sheet, the egg doesn’t break due to

- A) reduced impulse.
- B) reduced momentum.
- C) both of these
- D) neither of these

Answer: DDiff: 2Topic: Impulse 17) Compared with falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the

- A) carpeted floor provides a smaller impulse.
- B) stopping time is shorter on the carpet.
- C) stopping time is longer on the carpet.
- D) carpet provides a smaller impulse and a longer time.

Answer: CDiff: 2Topic: Impulse 18) To catch a fast-moving ball, you extend your hand forward before contact with the ball and let it ride backward in the direction of the ball’s motion. Doing this reduces the force of contact on your hand principally because the

- A) force of contact is reduced.
- B) relative velocity is less.
- C) time of contact is increased.
- D) time of contact is decreased.
- E) none of the above

Answer: CDiff: 1Topic: Impulse Changes Momentum 19) When you jump from an elevated position you usually bend your knees upon reaching the ground, which makes the time of the contact about 10 times that of a stiff-legged landing. In this way the average force your body experiences is

- A) less than 1/10 as great.
- B) more than 1/10 as great.
- C) about 1/10 as great.
- D) about 10 times as great.

Answer: CDiff: 1Topic: Impulse Changes Momentum20) If you can’t avoid being hit by a fast-moving object, you’ll suffer a smaller contact force if you can extend that force over a

- A) longer time.
- B) shorter time.
- C) both the same

Answer: ADiff: 1Topic: Impulse Changes Momentum 21) A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force on her hand is

- A) zero.
- B) less than the force applied to the cement block.
- C) the same as the force applied to the block.
- D) more than the force applied to the block.
- E) need more information

Answer: CDiff: 2Topic: Impulse Changes Momentum 22) Which produces more force: driving into a very massive concrete wall with no “give,” or having a head-on collision with an identical car moving toward you at the same speed?

- A) car
- B) wall
- C) both the same
- D) need more information

Answer: CDiff: 2Topic: Impulse Changes Momentum 23) Whether a truck comes to a stop by crashing into a haystack or a brick wall, the stopping force is

- A) greater with the haystack.
- B) greater with the brick wall.
- C) both the same

Answer: BDiff: 2Topic: Impulse Changes Momentum 24) Whether a truck comes to a stop by crashing into a haystack or a brick wall, the impulse is

- A) greater with the haystack.
- B) greater with the brick wall.
- C) both the same

Answer: CDiff: 2Topic: Impulse Changes Momentum25) When a boxer moves into an oncoming punch, the force experienced is

- A) decreased.
- B) increased.
- C) no different, but the timing is different.
- D) all of the above

Answer: BDiff: 2Topic: Impulse Changes Momentum 26) When a boxer is moving away from a punch, the force experienced is reduced because

- A) momentum transfer is reduced.
- B) the time of contact is increased.
- C) the force is less effective.
- D) all of the above

Answer: BDiff: 2Topic: Impulse Changes Momentum 27) A cannon recoils while firing a cannonball. The speed of the cannon’s recoil is relatively small because the

- A) force against the cannon is smaller than against the ball.
- B) momentum is mainly concentrated in the cannonball.
- C) cannon has much more mass than the cannonball.
- D) momentum of the cannon is smaller.

Answer: CDiff: 2Topic: Impulse Changes Momentum 28) A tiny gun made of a strong but very light material fires a bullet more massive than the gun itself. For such a weapon

- A) the target would be safer than the shooter.
- B) recoil problems would be lessened.
- C) conservation of energy would not hold.
- D) conservation of momentum would not hold.
- E) both conservation of energy and momentum would not hold.

Answer: ADiff: 2Topic: Impulse Changes Momentum 29) A heavy truck and a small car rolling down a hill at the same speed are forced to stop in the same amount of time. Compared with the force that stops the car, the force needed to stop the truck is

- A) greater.
- B) smaller.
- C) the same.

Answer: ADiff: 2Topic: Impulse Changes Momentum 30) The force that accelerates a rocket in outer space is exerted on the rocket by the

- A) rocket’s nose cone.
- B) rocket’s wings.
- C) atmospheric pressure.
- D) exhaust gases.
- E) none of the above

Answer: DDiff: 2Topic: Impulse Changes Momentum 31) The average braking force of a 1000-kg car moving at 10 m/s braking to a stop in 5 s is

- A) 1000 N.
- B) 2000 N.
- C) 3000 N.
- D) 4000 N.
- E) 5000 N.

Answer: BDiff: 2Topic: Impulse Changes Momentum 32) A falling 1-N apple hits the ground with a force of about

- A) 1 N.
- B) 2 N.
- C) 4 N.
- D) 10 N.
- E) need more information

Answer: EDiff: 3Topic: Impulse Changes Momentum 33) A bungee jumper attains a speed of 30 m/s just as the bungee cord begins to stretch. If the period of stretch is 2 s while coming to a halt, the jumper’s average deceleration is about

- A) 0.5
*g*. - B)
*g*. - C) 1.5
*g*. - D) 2
*g*.

Answer: CDiff: 3Topic: Impulse Changes Momentum 34) As Bronco Brown steps off a hovering high-flying helicopter and falls through the air, he experiences

- A) an impulse.
- B) an increasing speed.
- C) a decreasing acceleration.
- D) all of the above

Answer: DDiff: 3Topic: Impulse Changes Momentum35) The greater efficiency achieved with the curved blades of a Pelton wheel is due to

- A) bouncing.
- B) greater time of water impact.
- C) rotational momentum.
- D) divided impulse.

Answer: ADiff: 1Topic: Bouncing 36) A karate chop is more effective if one’s hand

- A) follows through upon impact.
- B) bounces upon impact.
- C) extends the time upon impact.

Answer: BDiff: 1Topic: Bouncing 37) A softer landing occurs when an falling object bounces from a surface

- A) in a extended time.
- B) quickly.
- C) either of these
- D) neither of these

Answer: ADiff: 1Topic: Bouncing 38) A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest. Both move with a combined momentum of

- A) less than 1 unit.
- B) more than 1 unit.
- C) 1 unit.
- D) need more information

Answer: CDiff: 3Topic: Bouncing 39) The change in momentum that occurs when a 1.0 kg ball traveling at 4.0 m/s strikes a wall and bounces back at 2.0 m/s is

- A) 2 kg m/s.
- B) 4 kg m/s.
- C) 6 kg m/s.
- D) 8 kg m/s.

Answer: CDiff: 3Topic: Bouncing40) The conservation of momentum is most closely related to

- A) Newton’s 1st law.
- B) Newton’s 2nd law.
- C) Newton’s 3rd law.
- D) Newton’s law of gravity

Answer: CDiff: 1Topic: Conservation of Momentum 41) When bullets are fired from an airplane in the forward direction, the momentum of the airplane is

- A) decreased.
- B) unchanged.
- C) increased.

Answer: ADiff: 1Topic: Conservation of Momentum 42) When Freddy Frog drops vertically from a tree onto a horizontally-moving skateboard, the speed of the skateboard

- A) decreases.
- B) increases.
- C) neither decreases nor increases.

Answer: ADiff: 2Topic: Conservation of Momentum 43) Freddy Frog drops vertically from a tree onto a horizontally-moving skateboard. The reason he doesn’t slip off the skateboard is due to

- A) inertia in motion.
- B) momentum change.
- C) friction between his feet and the board.

Answer: CDiff: 2Topic: Conservation of Momentum 44) You’re driving down the highway and a bug spatters into your windshield. Which undergoes the greater change in momentum during the time of contact?

- A) the bug
- B) your car
- C) both the same

Answer: CDiff: 2Topic: Conservation of Momentum45) An astronaut floating alone in outer space throws a baseball. If the ball moves away at 20 m/s, the astronaut will

- A) move in the opposite direction at 20 m/s.
- B) move in the opposite direction at a lower speed.
- C) move in the opposite direction at a higher speed.
- D) none of the above

Answer: BDiff: 2Topic: Conservation of Momentum 46) Recoil is noticeable if we throw a heavy ball while standing on roller skates. If instead we go through the motions of throwing the ball but hold onto it, our net recoil will be

- A) zero.
- B) the same as before.
- C) small, but noticeable.

Answer: ADiff: 2Topic: Conservation of Momentum 47) Two billiard balls having the same mass and speed roll toward each other. What is their combined momentum after they meet?

- A) zero
- B) half the sum of their original momentums
- C) twice the sum of their original momentums
- D) need more information

Answer: ADiff: 2Topic: Conservation of Momentum 48) If a monkey floating in outer space throws his hat away, the hat and the monkey will both

- A) move away from each other, but at different speeds.
- B) move away from each other at the same speed.
- C) move a short distance and then slow down.
- D) move a short distance and then go faster.
- E) come to a stop after a few minutes.

Answer: ADiff: 2Topic: Conservation of Momentum 49) An open freight car rolls friction free along a horizontal track in a pouring rain that falls vertically. As water accumulates in the car, the car’s speed

- A) increases.
- B) decreases.
- C) doesn’t change.
- D) need more information

Answer: BDiff: 3Topic: Conservation of Momentum50) A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of

- A) 0 kg m/s.
- B) 1 kg m/s.
- C) 2 kg m/s.
- D) 5 kg m/s.
- E) more than 5 kg m/s.

Answer: BDiff: 3Topic: Conservation of Momentum 51) A 2-kg rifle that is suspended by strings fires a 0.01-kg bullet at 200 m/s. The recoil velocity of the rifle is about

- A) 0.001 m/s.
- B) 0.01 m/s.
- C) 0.1 m/s.
- D) 1 m/s.
- E) none of these

Answer: DDiff: 3Topic: Conservation of Momentum 52) A 5-kg fish swimming at 1 m/s swallows an absent-minded 1-kg fish at rest. The speed of the larger fish after lunch is

- A) 1/2 m/s.
- B) 2/5 m/s.
- C) 5/6 m/s.
- D) 6/5 m/s.
- E) 1 m/s.

Answer: CDiff: 3Topic: Conservation of Momentum 53) A 5-kg shark swimming at 1 m/s swallows an absent-minded 1-kg fish swimming toward it at 4 m/s. The speed of the shark after his meal is

- A) 1/2 m/s.
- B) 1/5 m/s.
- C) 1/6 m/s.
- D) 2/3 m/s.
- E) 3/2 m/s.

Answer: CDiff: 3Topic: Conservation of Momentum 54) A fan attached to an ice sailcraft stalled on a windless day blows air into the sail that *bounces* backward upon impact. The boat

- A) moves in the direction of the wind impact force.
- B) does not move by this wind impact.
- C) moves, but in the opposite direction of the wind impact force.

Answer: ADiff: 3Topic: Conservation of Momentum55) If all people, animals, trains and trucks all over the world began to walk or run towards the east (opposite the direction of Earth’s spin), then

- A) Earth would spin a bit faster.
- B) Earth would spin a bit slower.
- C) Earth’s spin would not be affected at all.

Answer: BDiff: 3Topic: Conservation of Momentum 56) A golf ball moving forward with 1 unit of momentum strikes and bounces backward off a heavy bowling ball that is initially at rest and free to move. The bowling ball is set in motion with a momentum of

- A) less than 1 unit.
- B) more than 1 unit.
- C) 1 unit.
- D) not enough information

Answer: BDiff: 3Topic: Conservation of Momentum 57) Two identical gliders slide toward each other on an air track. One moves at 1 m/s and the other at 2 m/s. They collide, stick, and moves at

- A) 1/2 m/s.
- B) 1/3 m/s.
- C) 1/6 m/s.
- D) 3/4 m/s.
- E) 1.5 m/s.

Answer: ADiff: 3Topic: Collisions 58) A 5000-kg freight car moving at 2 m/s collides with a 10,000-kg freight car at rest. They couple upon collision and move away at

- A) 2 m/s.
- B) 1 m/s.
- C) 2/3 m/s.
- D) 1/3 m/s.

Answer: ADiff: 3Topic: Collisions 59) A 5000-kg freight car collides with a 10,000-kg freight car at rest. They couple upon collision and move at 2 m/s. What was the initial speed of the 5000-kg car?

- A) 4 m/s
- B) 5 m/s
- C) 6 m/s
- D) 8 m/s
- E) none of the above

Answer: CDiff: 3Topic: Collisions60) Consider massive gliders that slide friction-free along a horizontal air track. Glider A has a mass of 1 kg, a speed of 1 m/s, and collides with Glider B that has a mass of 5 kg and is at rest. If they stick upon collision, their speed after collision will be

- A) 1/4 m/s.
- B) 1/5 m/s.
- C) 1/6 m/s.
- D) 1 m/s.
- E) none of the above

Answer: CDiff: 3Topic: Collisions 61) A 1-kg glider and a 2-kg glider both slide toward each other at 1 m/s on an air track. They collide and stick. The combined mass moves at

- A) 0 m/s.
- B) 1/2 m/s.
- C) 1/3 m/s.
- D) 1/6 m/s.
- E) 1.5 m/s.

Answer: CDiff: 3Topic: Collisions 62) A sandbag motionless in outer space is hit by a three-times-as massive sandbag moving at 12 m/s. They stick together and move at a speed of

- A) 3 m/s.
- B) 4 m/s.
- C) 6 m/s.
- D) 8 m/s.
- E) none of the above

Answer: EDiff: 3Topic: Collisions 63) A red car has a head-on collision with an approaching blue car with the same magnitude of momentum. A green car driving with the same momentum as the other cars collides with an enormously massive wall. Which of the three cars will experience the greatest impulse?

- A) red car
- B) blue car
- C) green car
- D) all the same

Answer: DDiff: 3Topic: Collisions64) Two identical freight cars roll without friction (one at 1 m/s, the other at 2 m/s) toward each other on a level track. They collide, couple together, and roll away in the direction of

- A) the slower car.
- B) the faster car.
- C) neither, for they stop.

Answer: BDiff: 3Topic: Collisions 65) Two 5000-kg rail cars roll without friction (one at 1 m/s, the other at 2 m/s) toward each other on a level track. They collide, couple, and roll together with a combined momentum of

- A) zero.
- B) 5000 kg m/s.
- C) 10,000 kg m/s.
- D) 15,000 kg m/s.

Answer: BDiff: 3Topic: Collisions 66) Two identical objects in outer space, one moving at 2 m/s, the other at 1 m/s, have a head-on collision and stick together. Their combined speed after the collision is

- A) 0.5 m/s.
- B) 0.33 m/s.
- C) 0.67 m/s.
- D) 1.0 m/s.
- E) none of the above

Answer: ADiff: 3Topic: Collisions 67) Two vehicles with equal magnitudes of momentum traveling at right angles to each other undergo an inelastic collision. The combined wreck moves in a direction

- A) parallel to either of the cars before collision.
- B) at 45 degrees to the direction of either car before collision.
- C) at some angle other than 45 degrees.

Answer: BDiff: 2Topic: More Complicated Collisions 68) Two vehicles with equal magnitudes of momentum traveling at right angles to each other undergo an inelastic collision. The magnitude of momentum for the combined wreck is

- A) the same as the magnitude of momentum of either car before collision.
- B) less than the magnitude of momentum of either car before collision.
- C) greater than the magnitude of momentum of either car before collision.
- D) none of the above

Answer: CDiff: 2Topic: More Complicated Collisions 69) A firecracker bursts while freely falling. The combined momentum of its fragments

- A) equals the momentum of the firecracker at the time of burst
- B) cancels to the firecracker’s momentum at the time of bursting.
- C) cancels to zero.
- D) none of the above

Answer: ADiff: 2Topic: More Complicated Collisions 70) When a vertically falling firecracker bursts, the vector sum of momentum fragments

- A) in the horizontal direction cancels to zero.
- B) in the vertical direction equals the momentum of the firecracker before bursting.
- C) both of these
- D) neither of these

Answer: CDiff: 2Topic: More Complicated Collisions 71) A cannonball following a parabolic path explodes into fragments. The momentum of the fragments

- A) continue along the path as if the explosion didn’t occur.
- B) cancels to zero by vector addition.
- C) both of these
- D) neither of these

Answer: ADiff: 2Topic: More Complicated Collisions *Conceptual Physics, 12e*** (Hewitt)****Chapter 7 Energy**** **7.1 Multiple-Choice Questions 1) The work done in pushing a TV set a distance of 2 m with an average force of 20 N is

- A) 2 J.
- B) 10 J.
- C) 20 J.
- D) 40 J.
- E) 800 J.

Answer: DDiff: 1Topic: Work 2) The work you do when pushing a shopping cart twice as far while applying the same force is

- A) half as much.
- B) twice as much.
- C) four times as much.
- D) the same amount.

Answer: BDiff: 1Topic: Work 3) The work you do when pushing a shopping cart twice as far while applying twice the force is

- A) half as much.
- B) twice as much.
- C) four times as much.
- D) the same amount.

Answer: CDiff: 1Topic: Work 4) The work you do when pushing a shopping cart a given distance while applying twice as much force is

- A) half as much.
- B) twice as much.
- C) four times as much.
- D) the same amount.

Answer: BDiff: 1Topic: Work 5) No work is done by gravity on a bowling ball that rolls along a bowling alley because

- A) no force acts on the ball.
- B) little distance is covered by the ball.
- C) the force on the ball is at right angles to the ball’s motion.
- D) the ball’s speed remains constant.

Answer: CDiff: 1Topic: Work6) A 1000-kg car and a 2000-kg car are hoisted to the same height. Raising the more massive car requires

- A) less work.
- B) as much work.
- C) twice as much work.
- D) four times as much work.
- E) more than four times as much work.

Answer: CDiff: 1Topic: Work 7) The unit kilowatt-hour is a unit of

- A) energy.
- B) momentum.
- C) power.
- D) time.

Answer: ADiff: 1Topic: Work 8) One kilowatt-hour represents

- A) 1 N.
- B) 60 N/s.
- C) 60,000 W.
- D) 3.6 million joules.
- E) none of these

Answer: DDiff: 2Topic: Work 9) Which task requires more work?

- A) lifting the 50-kg sack 2 meters
- B) lifting the 25-kg sack 4 meters
- C) both require the same
- D) need more information

Answer: CDiff: 2Topic: Work 10) The amount of work done on a heavy box carried by Nellie across a room at a constant speed

- A) depends on the weight of the box.
- B) depends on the distance walked.
- C) depends on both weight of the box and distance walked.
- D) is none.
- E) none of the above

Answer: DDiff: 2Topic: Work11) If you do work on a skateboard loaded with friends in one-third the usual time, you expend

- A) one third as much power.
- B) the usual power.
- C) three times the usual power.
- D) need more information.

Answer: CDiff: 2Topic: Work 12) The power expended doing 100 J of work in 50 s is

- A) 1/2 W.
- B) 2 W.
- C) 4 W.
- D) 50 W.
- E) 5,000 W.

Answer: BDiff: 2Topic: Work 13) The power required to exert 4-N force over 3 meters in 2 seconds is

- A) 4 W.
- B) 6 W.
- C) 8 W.
- D) 12 W.
- E) none of the above

Answer: BDiff: 2Topic: Work 14) Both a 50-kg sack is lifted 2 meters from the ground and a 25-kg sack is lifted 4 meters in the same time. The power expended in raising the 50-kg sack is

- A) twice as much as the 25-kg sack.
- B) half as much as the 25-kg sack.
- C) the same.
- D) need more information

Answer: CDiff: 2Topic: Work 15) A toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed using 1000 J of work, is

- A) 20 W.
- B) 50 W.
- C) 100 W.
- D) 1000 W.
- E) 20,000 W.

Answer: BDiff: 2Topic: Work16) The center of a long uniform log is raised to shoulder level while the other end is on the ground. If instead, the *end *of the log is raised to shoulder level, the work required is

- A) half.
- B) the same.
- C) twice.

Answer: ADiff: 3Topic: Work 17) An object has gravitational potential energy due to its

- A) speed.
- B) acceleration.
- C) momentum.
- D) location.
- E) none of the above

Answer: DDiff: 1Topic: Potential Energy 18) Relative to an initial height, an object raised twice as high has a gravitational potential energy

- A) half as much
- B) twice as much.
- C) four times as much.
- D) need more information

Answer: BDiff: 1Topic: Potential Energy 19) A crate of grapes lifted 10 meters gains 200 J of potential energy. If the same crate is instead lifted 20 meters, its gain in potential energy is

- A) half as much.
- B) the same.
- C) twice as much.
- D) four times as much.
- E) more than four times as much.

Answer: CDiff: 1Topic: Potential Energy 20) When a drawn bow of potential energy 40 J is fired, the arrow will *ideally* have a kinetic energy

- A) less than 40 J.
- B) more than 40 J.
- C) of 40 J.

Answer: CDiff: 1Topic: Potential Energy21) A clerk can lift cylindrical packages 1 meter vertically, or can roll them up a 2-meter-long ramp to the same elevation. With the ramp, the applied force required is about

- A) half as much.
- B) the same.
- C) twice as much.
- D) four times as much.

Answer: ADiff: 2Topic: Potential Energy 22) A 2-kg ball is held 4 m above the ground. Relative to the ground its potential energy is

- A) 6 J.
- B) 8 J.
- C) 32 J.
- D) 80 J.
- E) more than 80 J.

Answer: DDiff: 2Topic: Potential Energy 23) A 2-kg box of taffy candy has 40 J of potential energy relative to the ground. Its height above the ground is

- A) 1 m.
- B) 2 m.
- C) 3 m.
- D) 4 m.
- E) none of the above

Answer: BDiff: 2Topic: Potential Energy 24) The ram of a pile driver drops onto the top of an iron beam, driving it partway into the ground. The distance that the beam sinks into the ground depends on the

- A) initial height of the ram.
- B) initial potential energy of the ram.
- C) kinetic energy of the ram when it first hits the beam.
- D) all of the above

Answer: DDiff: 2Topic: Potential Energy 25) An object that has kinetic energy must be

- A) moving.
- B) falling.
- C) at an elevated position.
- D) at rest.
- E) none of the above

Answer: ADiff: 1Topic: Kinetic Energy 26) Two identical golf carts move at different speeds. The faster cart has twice the speed and therefore has

- A) twice the kinetic energy.
- B) four times the kinetic energy.
- C) eight times the kinetic energy.
- D) none of the above

Answer: BDiff: 2Topic: Kinetic Energy 27) A feather and a coin dropped in a vacuum fall with equal

- A) forces due to gravity.
- B) accelerations.
- C) kinetic energies.
- D) none of these

Answer: BDiff: 2Topic: Kinetic Energy 28) A melon is tossed straight upward with 100 J of kinetic energy. If air resistance is negligible the melon will return to its initial level with a kinetic energy of

- A) less than 100 J.
- B) more than 100 J.
- C) 100 J.
- D) need more information

Answer: CDiff: 2Topic: Kinetic Energy 29) A melon is projected into the air with 100 J of kinetic energy in the presence of *air resistance*. When it returns to its initial level its kinetic energy is

- A) less than 100 J.
- B) more than 100 J.
- C) 100 J.
- D) need more information

Answer: ADiff: 2Topic: Kinetic Energy 30) Danny Diver weighs 500 N and steps off a diving board 10 m above the water. Danny hits the water with kinetic energy of

- A) 10 J.
- B) 500 J.
- C) 510 J.
- D) 5000 J.
- E) more than 5000 J.

Answer: DDiff: 2Topic: Kinetic Energy31) Which has greater kinetic energy?

- A) a car traveling at 30 km/hr
- B) a car of half the mass traveling at 60 km/hr
- C) both the same
- D) need more information

Answer: BDiff: 3Topic: Kinetic Energy 32) Neglecting air resistance, Sammy Smarts on a high ladder releases a ball that strikes the ground with 100 J of kinetic energy. If he were to instead throw the ball straight upward, it will soon reach the ground with a kinetic energy of

- A) less than 100 J.
- B) 100 J.
- C) more than 100 J.

Answer: BDiff: 3Topic: Kinetic Energy 33) If a Ping-Pong ball and a golf ball both move in the same direction with the same amount of kinetic energy, the speed of the Ping-Pong ball must be

- A) less than the golf ball.
- B) more than the golf ball.
- C) both the same
- D) need more information

Answer: BDiff: 3Topic: Kinetic Energy 34) Two identical particles move toward each other, one twice as fast as the other. Just before they collide, one has a kinetic energy of 25 J and the other 50 J. At this instant their total kinetic energy is

- A) 25 J.
- B) 50 J.
- C) 75 J.
- D) none of the above
- E) need more information

Answer: CDiff: 3Topic: Kinetic Energy 35) When Joshua brakes his speeding bicycle to a stop, kinetic energy is transformed to

- A) potential energy.
- B) energy of motion.
- C) energy of rest.
- D) heat.

Answer: DDiff: 1Topic: Work-Energy Theorem36) A bicycle that travels twice as fast as another when braking to a stop will skid

- A) twice as far.
- B) four times as far.
- C) eight times as far
- D) sixteen times as far.
- E) depends on the bike’s mass

Answer: BDiff: 2Topic: Work-Energy Theorem 37) A bicycle that travels four as fast as another when braking to a stop will skid

- A) twice as far.
- B) four times as far.
- C) eight times as far
- D) sixteen times as far.
- E) depends on the mass of the bike

Answer: DDiff: 2Topic: Work-Energy Theorem 38) A motorcycle moving at 50 km/h skids 10 m with locked brakes. How far will it skid with locked brakes when traveling at 150 km/h?

- A) 10 m
- B) 30 m
- C) 50 m
- D) 90 m

Answer: DDiff: 2Topic: Work-Energy Theorem 39) A cannonball has more kinetic energy than the recoiling cannon from which it is fired because the force on the ball

- A) is more concentrated.
- B) meets less resistance than the cannon on the ground.
- C) acts over a longer distance.

Answer: CDiff: 2Topic: Work-Energy Theorem 40) About 40 J is required to push a crate 4 m across a floor. If the push is in the same direction as the motion of the crate, the force on the crate is about

- A) 4 N.
- B) 10 N.
- C) 40 N.
- D) 160 N.

Answer: BDiff: 2Topic: Work-Energy Theorem41) If the speed of a bicycle is reduced to half before skidding to a stop, it will skid

- A) one-eighth as far.
- B) one-fourth as far.
- C) one-half as far.
- D) none of the above

Answer: BDiff: 3Topic: Work-Energy Theorem 42) Which requires the most amount of work by the brakes of a car?

- A) slowing down from 100 km/h to 70 km/h
- B) slowing down from 70 km/h to a stop
- C) equal amounts for both

Answer: ADiff: 3Topic: Work-Energy Theorem 43) A 2500-N pile-driver ram falls 10 m and drives a post 0.1 m into the ground. The average impact force on the ram is

- A) 2,500 N.
- B) 25,000 N.
- C) 250,000 N.
- D) 2,500,000 N.

Answer: CDiff: 3Topic: Work-Energy Theorem 44) Two identical arrows, one with twice the *kinetic energy* of the other, are fired into a bale of hay. Compared with penetration of the slow arrow, the faster arrow penetrates

- A) the same distance.
- B) twice as far.
- C) four times as far.
- D) more than four times as far.
- E) none of the above

Answer: BDiff: 3Topic: Work-Energy Theorem 45) Two identical arrows, one with twice the *speed *of the other, are fired into a bale of hay. Compared with penetration of the slow arrow, the faster arrow penetrates

- A) the same distance.
- B) two times as far.
- C) four times as far.
- D) more than four times as far.
- E) none of the above

Answer: CDiff: 3Topic: Work-Energy Theorem46) A ball rolling down an incline has its maximum potential energy at

- A) the top.
- B) a quarter of the way down.
- C) halfway down.
- D) the bottom.

Answer: ADiff: 1Topic: Conservation of Energy 47) A ball rolling down an incline has its maximum kinetic energy at

- A) the top.
- B) halfway down.
- C) three-quarters of the way down.
- D) the bottom.

Answer: DDiff: 1Topic: Conservation of Energy 48) The bob of a simple pendulum has its maximum kinetic energy at the

- A) top of its swing.
- B) bottom of its swing.
- C) midpoint between top and bottom.
- D) at all points along its path of swing.

Answer: BDiff: 1Topic: Conservation of Energy 49) After rolling halfway down an incline, a marble’s kinetic energy is

- A) less than its potential energy.
- B) greater than its potential energy.
- C) the same as its potential energy.

Answer: CDiff: 2Topic: Conservation of Energy 50) A block of ice sliding down an incline has half its maximum kinetic energy

- A) at the top.
- B) at the bottom.
- C) halfway down.
- D) need more information

Answer: CDiff: 2Topic: Conservation of Energy51) A light aluminum ball and a heavy lead ball of the same size roll down an incline. When they are halfway down the incline, they will have identical

- A) kinetic energies.
- B) potential energies.
- C) momentum.
- D) inertias.
- E) none of the above

Answer: EDiff: 2Topic: Conservation of Energy 52) When wind encounters a wind turbine that produces energy, wind speed on the downside of the blades is

- A) slowed.
- B) speeded up.
- C) not affected.

Answer: ADiff: 2Topic: Conservation of Energy 53) Strictly speaking, more fuel is consumed by your car if the air conditioner, headlights, or even a radio is turned on. This statement is

- A) false.
- B) true only if the car’s engine is running.
- C) true.

Answer: CDiff: 2Topic: Conservation of Energy 54) A circus diver drops from a high pole into water far below. When he is halfway down

- A) his potential energy is halved.
- B) he has gained an amount of kinetic energy equal to half his initial potential energy.
- C) his kinetic energy and potential energy are equal.
- D) all of the above
- E) none of the above

Answer: DDiff: 2Topic: Conservation of Energy 55) Acrobat Bart at the circus drops vertically onto the end of a see-saw, with his partner Art equidistant from the fulcrum at the other end. Art is propelled straight upward a distance twice that of Bart’s dropping distance. Neglecting inefficiencies we see

- A) the masses of Art and Bart are equal.
- B) Art has half the mass of Bart.
- C) need more information

Answer: BDiff: 3Topic: Conservation of Energy 56) A 1-kg ball dropped from 2 m rebounds only 1.5 m after hitting the ground. The amount of energy converted to heat is about

- A) 0.5 J.
- B) 1.0 J.
- C) 1.5 J.
- D) 2.0 J.
- E) more than 2.0 J.

Answer: EDiff: 3Topic: Conservation of Energy 57) Although perpetual motion is the natural order of things in the universe

- A) it follows that machines can operate and do work by perpetual motion.
- B) no perpetual-motion device that multiplies energy exists.
- C) both of these are false statements

Answer: BDiff: 1Topic: Machines 58) A common pulley acts similar to a

- A) hydraulic press.
- B) gear.
- C) common lever.
- D) tension producer.

Answer: CDiff: 1Topic: Machines 59) A hydraulic press, like an inclined plane, is capable of increasing energy.

- A) sometimes true
- B) always false
- C) always true
- D) sometimes false

Answer: BDiff: 1Topic: Machines 60) When properly used, a hydraulic press, like a wheel and axle, is capable of multiplying force input.

- A) A true statement.
- B) A false statement.
- C) Yes, and in special cases, energy as well.

Answer: ADiff: 1Topic: Machines 61) A hydraulic jack is used to lift objects such as automobiles. If the input force is 200 N over a distance of 1 meter, the output force over a distance of 0.1 meter is ideally

- A) 200 N.
- B) 500 N.
- C) 1000 N.
- D) 2000 N.
- E) none of the above

Answer: DDiff: 2Topic: Machines 62) Phil applies 100 N to a pulley system and raises a load one-tenth of his downward pull. Ideally, the weight of the load is

- A) 100 N.
- B) 1000 N.
- C) 10,000 N.
- D) more than 10,000 N

Answer: BDiff: 2Topic: Machines 63) A hydraulic press has its input piston depressed 20 centimeters while the output piston is raised 1 centimeter. A 1-newton input can lift a load of

- A) 1 N.
- B) 10 N.
- C) 15 N.
- D) 20 N.
- E) none of the above

Answer: DDiff: 2Topic: Machines 64) A machine puts out 100 watts of power for every 1000 watts put into it. The efficiency of the machine is

- A) 10%.
- B) 50%.
- C) 90%.
- D) 110%.
- E) none of the above

Answer: ADiff: 2Topic: Efficiency 65) A jack system will increase the potential energy of a heavy load by 1000 J with a work input of 2000 J. The efficiency of the jack system is

- A) 10%.
- B) 20%.
- C) 50%.
- D) 80%.
- E) need more information

Answer: CDiff: 2Topic: Efficiency 66) A miracle car with a 100% efficient engine burns fuel having a 40-megajoules-per-liter energy content. If air drag and overall frictional forces at highway speeds totals 1000 N, what distance per liter can be achieved on the highway?

- A) 30 km
- B) 40 km
- C) 50 km
- D) more than 50 km
- E) need more information

Answer: BDiff: 3Topic: Efficiency 67) A car’s engine is 20% efficient. When cruising, the car encounters an average retarding force of 1000 N. If the energy content of fuel is 40 megajoules per liter, how many kilometers per liter does the car achieve?

- A) 8
- B) 10
- C) 12
- D) 14
- E) none of the above

Answer: ADiff: 3Topic: Efficiency 68) Earth’s primary energy source is

- A) the Sun.
- B) fossil fuel.
- C) electricity.
- D) geothermal.

Answer: ADiff: 1Topic: Sources of Energy 69) Hydro and wind power are indirect forms of

- A) solar energy.
- B) fossil fuels deep down.
- C) nuclear energy in Earth’s interior.
- D) none of the above

Answer: ADiff: 1Topic: Sources of Energy70) A machine that promises more energy output than input is

- A) a fantasy.
- B) commonplace in today’s technology.
- C) a long-shot worth investing in.

Answer: ADiff: 1Topic: Sources of Energy 71) The most concentrated form of energy is

- A) wind.
- B) fossil fuel.
- C) geothermal.
- D) nuclear.

Answer: DDiff: 1Topic: Sources of Energy 72) The exhaust product from a hydrogen fuel cell is

- A) carbon dioxide.
- B) methane.
- C) pure water.
- D) nitric acid.

Answer: CDiff: 1Topic: Sources of Energy 73) Which of these is not a form of solar energy?

- A) wind energy
- B) fossil fuel energy
- C) geothermal energy
- D) hydroelectric power

Answer: CDiff: 2Topic: Sources of Energy 74) Solar power is commonly used to produce

- A) heat.
- B) electricity.
- C) both of these

Answer: CDiff: 2Topic: Sources of Energy 75) Hydrogen, like electricity, is

- A) an energy source.
- B) not an energy source.
- C) a source of both thermal and electric power.

Answer: BDiff: 2Topic: Sources of Energy76) A primary difference between momentum and kinetic energy is

- A) momenta can cancel; kinetic energy cannot.
- B) kinetic energy can cancel; momenta cannot.
- C) either of the above depending on circumstances
- D) none of the above

Answer: ADiff: 1Topic: Energy/Momentum 77) Impulse involves the time that a force acts, whereas work involves the

- A) distance that a force acts.
- B) time and distance that a force acts.
- C) acceleration that a force produces.

Answer: ADiff: 1Topic: Energy/Momentum 78) A moving object has

- A) speed.
- B) velocity.
- C) momentum.
- D) energy.
- E) all of these

Answer: EDiff: 1Topic: Energy/Momentum 79) If an all-electric car has kinetic energy, then it also must have

- A) impulse.
- B) momentum.
- C) acceleration.
- D) force.
- E) none of the above

Answer: BDiff: 1Topic: Energy/Momentum 80) If the speed of a motor scooter doubles, which of the following also doubles?

- A) momentum
- B) kinetic energy
- C) acceleration
- D) all of the above

Answer: ADiff: 1Topic: Energy/Momentum81) When a cannon is fired, it recoils as the cannonball is set in motion. The cannon and cannonball ideally acquire equal

- A) but opposite amounts of momentum.
- B) amounts of kinetic energy.
- C) both of these
- D) neither of these

Answer: ADiff: 2Topic: Energy/Momentum 82) When you and your snowboard are in motion, which of the following can be zero?

- A) momentum
- B) kinetic energy
- C) mass
- D) inertia
- E) none of the above

Answer: EDiff: 2Topic: Energy/Momentum 83) A roller skate at rest may have

- A) speed.
- B) velocity.
- C) momentum.
- D) energy.

Answer: DDiff: 2Topic: Energy/Momentum 84) Two 2-m/s pool balls roll toward each other and collide. Suppose after bouncing apart each moves at 4 m/s. This collision violates the conservation of

- A) momentum.
- B) energy.
- C) both momentum and energy.
- D) none of the above

Answer: BDiff: 2Topic: Energy/Momentum 85) Compared to the recoiling cannon, a fired cannonball has a

- A) greater momentum.
- B) greater kinetic energy.
- C) smaller speed.
- D) all of the above

Answer: BDiff: 2Topic: Energy/Momentum86) A golf ball is thrown at and bounces backward from a massive bowling ball that is initially at rest. After the collision, compared to the golf ball, the bowling ball has more

- A) momentum, but less kinetic energy.
- B) kinetic energy, but less momentum.
- C) momentum and more kinetic energy.
- D) need more information

Answer: ADiff: 3Topic: Energy/Momentum 87) A piece of taffy slams into and sticks to an identical piece of taffy at rest. The momentum of the combined pieces after the collision is the same as before the collision, but this is not true of the kinetic energy, which partly degrades into heat. What percentage of the kinetic energy becomes heat?

- A) 0%
- B) 25%
- C) 50%
- D) 75%
- E) need more information

Answer: CDiff: 3Topic: Energy/Momentum 88) Newton’s Cradle consists of an aligned row of identical elastic balls suspended by strings so they barely touch one another. When two balls are raised from one end and released, they strike the row and two balls pop out from the other end. If instead, one ball popped out with twice the speed of the two, this would violate

- A) momentum conservation.
- B) energy conservation.
- C) both of these
- D) none of these

Answer: BDiff: 3Topic: Energy/Momentum