momentum and impulse

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

1 unit

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

1/10th as a great

If several balls are thrown straight up with different initial speeds, the quantity that will have the same value along their paths is their

acceleration

A rubber ball and a lump of putty have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The putty sticks to the wall. Which objects experiences the greater momentum change?

ball

A cannon recoils while firing a cannonball. The speed of the cannon's recoil is relatively small because the

cannon has much more mass than the cannonball.

A freight car moves along a frictionless level railroad track at constant speed. The freight car is open on top. A large load of coal is suddenly dumped into the car. What happens to the speed of the freight car?

decreases

Identical forces act for the same length of time on two different masses. The change in momentum of the smaller mass is

equal to the change in momentum of the larger mass.

Impulse is a scalar quantity.

false

The impulse delivered to an object is equal to the change in the object's velocity.

false

When objects stick together after colliding, the collision is completely elastic.

false

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

momentum

If a monkey floating in outer space throws his hat away, the hat and the monkey will both

move away from each other at different speeds

An astronaut floating alone in outer space throws a baseball. If the ball moves away at 20 m/s, the astronaut will

move in the opposite direction of the ball at a slower speed

Two different masses have equal, non-zero kinetic energies. The momentum of the smaller mass is

smaller than the momentum of the larger mass

An open railroad car is coasting horizontally along frictionless rails. A girl on board starts throwing coal backward straight off the car. As a result, the railroad car

speeds up

An artillery shell explodes in midair and breaks up into many fragments. Which of the following statements are true regarding conditions immediately before and immediately after the explosion: I. The total momentum of the fragments is equal to the original momentum of the shell. II. The total kinetic energy of the fragments is equal to the original kinetic energy of the shell.

statement 1 only

Compared with falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the

stopping time is longer on carpet

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

the same as the force applied to the block.

When a boxer is moving away from a punch, the force experienced is reduced because

the time of contact is increased

A person standing on a horizontal frictionless floor might be able to move by

throwing a shoe

Internal forces cannot change the total momentum of a system.

true

Linear momentum is a vector quantity.

true

The net force acting on an object is equal to the rate of change of its momentum.

true

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

twice