chapter 7 test

a 2-kg ball is thrown at 3m/s. what is the balls momentum?

6 kgm/s

a 100 kg free floating astronaut fires 0.10 kg of gas at a speed of 50 m/s from her propulsion pistol. what is the astronauts recoil speed?

0.05 m/s

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. the bowling ball with its putty passenger will then be set in motion with a momentum of

1 kgm/s

a 8 kg blob of clay moving horizontally at 2 m/s hits a 4 kg blob of clay at rest. what is the speed of the two blobs such together immediately after the collision?

1.3 m/s

superman is at rest in space when he throws an asteroid that has more mass than he does. which moves faster, superman or the asteroid?

superman

a ball is moving at 3 m/s and has a momentum of 48 kg m/s. what is the ball's mass?

12 kg

assume that a 20 kg ball moving at 7 m/s strikes a wall perpendicularly and rebounds elastically at the same period. what is the amount of impulse given to the wall?

280 Ns

a 4-kg ball has a momentum of 12-kgm/s. what is the ball's speed?

3 m/s

a 10 kg cement block moving horizontally at 2 m/s plows into a pillow and comes to a stop in 0.5 m/s. what is the average impact force on the pillow?

40 N

what is the average momentum of a 50 kg runner who covers 400 m in 50 s?

400 kgm/s

which of the following has the largest momentum?

a pickup truck traveling down the highway

A car traveling along the highway needs a certain amount of force exerted on it to stop. More stopping force may be required when the car has

all of the above

a karate expert executes a swift blow and severs a cement block with her bare hand

all of the above

the force of an apple hitting the ground depends upon

all of the above

a cannon recoils from launching a cannonball. The speed of the cannon's recoil is small because the

cannon has far more mass than the cannonball

the force that accelerates a rocket into outer space is exerted on the rocket by the

exhaust gases

While rollerblading, Granny collides with her tiny grandson Ambrose who is at rest. Ignoring any friction effects, Ambrose's speed after the collision will be greatest when __________.

he and granny make a bouncing collision, each going separate ways

a cannonball shot from a long-barrel cannon travels faster than one shot from a short-barrel cannon because the cannonball receives a greater

impulse

the momentum change of an object is equal to the

impulse acting on it

the reason padded dashboard are used in cars is that they

increase the time of impact in a collision

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

less than 1 unit

a small economy car (low mass) and a limousine (high mass) are pushed from rest across a parking lot, equal distances with equal forces. the car that receives more kinetic energy is the

limousine

the momentum of an object is defined as the object's

mass times its velocity

two objects, a and b, have the same size and shape, but a is twice as heavy as b. when they are dropped simultaneously from a tower, they reach the ground at the same time, but a has a higher

momentum

Suppose an astronaut in outer space wishes to play solitary "throw, bounce, and catch" game by tossing a ball against a very massive and perfectly elastic concrete wall. If the ball is as massive as the astronaut, then

the astronaut will never catch the first bounce

a ping-pong ball launcher is fired. compared to the impulse on the ball, the impulse on the launcher is

the same

momentum of a system is conserved only when

there is no net external force acting on the system

compared to a sports car moving at 30 miles per hour, the same sports car moving at 60 miles per hour has

twice as much momentum

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 velocity will be

zero

two gliders having the same mass and speed move toward each other on an air track and stick together. after he collision the velocity of the gliders is

zero