Physical Science - Quiz 4

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

doubled

A boy fired a spring-loaded Ping-Pong ball gun. a. the forces on the ball and gun are equal and opposite b. the accelerations of the ball and gun are equal and opposite c. the impulses on the ball and gun are equal and opposite d. B and C only e. A and C only

e. A and C only

A ball is moving at 4 m/s and has a momentum of 48 kg • m/s. What is it's mass?

12 kg

An 8 kg ball has a speed of 20 m/s. It's momentum is

160 kg • m/s

A 10 kg ball has a momentum of 20 kg • m/s. What is the ball's speed?

2 m/s

A force of 2500 N is exerted on a car for 2 s. What is the impulse applied to the car?

5,000 N • s

A 5,000 kg freight car crashes 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 5,000 kg freight car?

6 m/s

You use a straw for a pea shooter. The speed of the pea emerging from the straw when you blow through it will be greater if the straw is a. cut in half b. full length c. either cut in half or full length

b. full length

Suppose a gun were made of strong lightweight material with a pellet that is more massive than the gun. Then firing speed is greater for the a. pellet b. recoiling gun c. both are the same d. none of the above

b. recoiling gun

The speed of a bullet fired from a gun will be about the same as the speed of the recoiling gun a. when momentum is conserved b. because velocity is conserved c. when both velocity and momentum are conserved d. if the masses of the bullet and gun are equal e. none of the above

d. if the masses of the bullet and gun are equal

In an ideally elastic collision a. there's no lasting deformation b. there is lasting deformation c. there's no generation of heat d. A and B only e. A and C only

e. A and C only

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

a. greater

It is correct to say that impulse is equal to a. momentum b. the change in momentum c. the force multiplied by the distance the force acts d. all of the above e. none of the above

b. the change in momentum

A heavy truck and a small truck roll down a hill. Neglecting friction, at the bottom of the hill the heavy truck has greater a. speed b. acceleration c. momentum d. all of the above e. none of the above

c. momentum

An object in motion will continue in motion with a. acceleration b. impulse c. momentum d. all of the above e. none of the above

c. momentum

In order to catch a fast-moving softball with your bare hand, you extend your hand forward just before the catch and then let the ball ride backward with your hand. Doing this reduces the catching force because the a. relative velocity is less b. relative velocity is more c. time of catch is increased d. time of catch is decreased e. none of the above

c. time of catch is increased

The force that accelerates a rocket in outer space is exerted on the rocket by the a. rocket's engine b. rocket's Wings c. atmospheric pressure d. exhaust gases e. none of the above

d. exhaust gases