Chapter 6

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

A

A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed? A)3 m/s B) 48 m/s C) 12 m/s D) 4 m/s E) none of these

A

A 5-kg fish swimming at a speed of 1 m/s swallows an absent-minded 1-kg fish at rest. The speed of the larger fish after this lunch is A) 5/6 m/s. B) 6/5 m/s. C) 1 m/s. D) 2/5 m/s. E) 1/2 m/s.

A

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 to the force that stops the car, the force needed to stop the truck is A )greater. B) the same. C) smaller.

A

It is correct to say that impulse is equal to A) the change in momentum it produces. B) momentum. C) velocity multiplied by time. D) the force multiplied by the distance the force acts.

A

)A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball that is initially at rest on a frictionless surface. The speed of the putty thereafter is A)1/5 m/s. B) 1/6 m/s. C) 1/4 m/s. impossible to solve with the information given.

B

An astronaut , floating alone in outer space, throws a baseball. If the ball floats away at a speed of 20 meters per second, the astronaut will A) move in the opposite direction but at a higher speed. B) move in the opposite direction, but at a lower speed. C) not move as stated in any of the above choices. D move in the opposite direction at a speed of 20 m/s.

B

When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, you make the time of the impact about 10 times as great as for a stiff-legged landing. In this way the average force your body experiences is A)less than 1/10 as great. B) about 1/10 as great. C) more than 1/10 as great. D) about 10 times as great.

B

A 5000-kg freight car moving at 2 m/s runs into a 10,000-kg freight car at rest. They couple upon collision and move away as one body at A)1 m/s. B) 2 m/s. C) 2/3 m/s. D) 1/3 m/s.

C

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) unchanged. B) zero. C) doubled. D) quadrupled.

C

A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force experienced by her hand is A)less than the force applied to the cement block. B) impossible to predict without additional information. C) identical to the force applied to the block. D) more than the force applied to the block. E) zero.

C

A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest. After the putty sticks to the ball, both move with a combined momentum of A)not enough information B) less than 1 unit. C) 1 unit. D) more than 1 unit.

C

A rifle of mass 2 kg is suspended by strings. The rifle fires a bullet of mass 0.01 kg at a speed of 200 m/s. The recoil velocity of the rifle is about A)0.01 m/s. B) 0.001 m/s. C) 1 m/s. D) 0.1 m/s.

C

A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because the A)force against the rifle is smaller than against the bullet. B)momentum of the rifle is smaller. C) rifle has much more mass than the bullet. D) momentum is mainly concentrated in the bullet.

C

Compared to 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) carpet provides a smaller impulse and a longer time. C) stopping time is longer on the carpet. stopping time is shorter on the carpet.

C

The force that accelerates a rocket in outer space is exerted on the rocket by the A)rocket's wings. B) rocket's nose cone. C) exhaust gases. D) none of these E) atmospheric pressure.

C

Two objects have the same size and shape, but one is much heavier than the other. When they are dropped simultaneously from a tower, they reach the ground at the same time, but the heavier one has a greater A)speed. B)acceleration. C) momentum. D) none of these E) all of these

C

Which of the following has the largest momentum relative to the Earth's surface? A) a dog running down the street B)the Science building on campus C)a pickup truck speeding along a highway D) a Mack truck parked in a parking lot E)a tightrope walker crossing Niagara Falls

C

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

C

A 1000-kg car moving at 10 m/s brakes to a stop in 5 s. A)4000 N. B) 5000 N. C) 1000 N. D) 2000 N. 3000 N.

D

A 1000-kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is A)P5000 N. B) 1000 N. C) 4000 N. D) 2000 N.

D

Padded dashboards in cars are safer in an accident than nonpadded ones because an occupant hitting the dash has A)increased momentum. B) decreased impulse. C) decreased time of impact. D) increased time of impact.

D

The change in momentum, in kg m/s, that occurs when a 1.0 kg ball travelling at 4.0 m/s strikes a wall and bounces back at 2.0 m/s is A) 8. B) 2. C) 4. D) 6.

D

To catch a ball, a baseball player extends the hand forward before impact with the ball and then lets it ride backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because the A) none of these B) relative velocity is less. C) time of impact is decreased. D) time of impact is increased.

D

A 5000-kg freight car runs into a 10,000-kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000-kg car? A)none of these B) 4 m/s C) 5 m/s D) 8 m/s E) 6 m/s

E