Physics chapter 8

If the momentum of an object changes and its mass remains constant, a. it is acceleration (or decelerating) b. there is a force acting on it c. its velocity is changing d. all of the above e. none of the above

d. all of the above

A collision is considered elastic if a. there is no lasting deformation b. the objects don't stick together c. the objects that collide don't get warmer d. after the collision, the objects have the same shape as before the collision e. all of the above

e. all of the above

In order to increase the final momentum of a golf ball, we could a. increase the force acting on it b. follow through when hitting the ball c. increase the time of contact with the ball d. swing as hard as possible e. all of the above

e. all of the above

The force of an apple hitting the ground depends upon a. the speed of the apple just before it hits b. the time of impact with the ground c. whether or not the apple bounces d. air resistance on the apple as it falls e. all of the above

e. all of the above

A 1-N apple falls to the ground. The apple hits the ground with an impact force of a. 1 N b. 2 N c. 4 N d. 9.8 N e. not enough information to say

a. 1 N

A truck travels north with a momentum of 2,600 kg*km/s, and a motorcycle heads west with a momentum of 1,500 kg*km/s. The motorcycle hits the truck. If the two vehicles collide and then stick together, what is the momentum and direction of travel? a. The vehicles travel with a momentum of 3,000 kg*km/s in the NW direction b. The vehicles travel with a momentum of 6,000 kg*km/s in the SW direction c. The vehicles travel with a momentum of 3,000 kg*km/s in the NW direction d. The vehicles travel with a momentum of 6,000 kg*km/s in the SW direction

a. The vehicles travel with a momentum of 3,000 kg*km/s in the NW direction

A cannon fires a cannonball. The speed of the cannonball will be the same as the speed of the recoiling cannon a. if the mass of the cannonball equals the mass of the cannon b. because momentum is conserved c. because velocity is conserved d. because both velocity and momentum are conserved e. none of the above

a. if the mass of the cannonball equals the mass of the cannon

The momentum change of an object is equal to the a. impulse acting on it b. velocity change of the object c. force acting on it d. force acting on it times its velocity e. objects mass times the force acting on it

a. impulse acting on it

The momentum of an object is defined as the object's a. mass times its velocity b. force times the time interval c. force times its acceleration d. mass times its acceleration e. velocity times the time interval

a. mass times its velocity

A meteor that originally was heading south breaks up into two chucks. One of the chunks moves southwest. The second chunk was not immediately found, but scientists guessed that they should look for an object heading a. southeast b. northeast c. southwest d. northwest

a. southeast

The force that accelerates a rocket into outer space is exerted on the rocket by a. the exhaust gases b. Earth's gravity c. atmospheric pressure d. rocket's wings e. none of the above

a. the exhaust gases

A piece of putty moving with 2 units of momentum strikes and sticks to heavy bowling ball that is initially at rest. After the putty sticks to the ball, both are set in motion with a combined momentum that is a. less than 2 units b. 2 units c. more than 2 units d. there is not enough information to say

b. 2 units

A ball is moving at 6.0 m/s and has a momentum of 24.0 kg*m/s. What is the ball's mass? a. 0.3 kg b. 4.0 kg c, 24.0 kg d. 144.0 kg e. none of the above

b. 4.0 kg

A 4.0 kg ball has a momentum of 20.0 kg*m/s. What is the ball's speed? a. 0.2 m/s b. 5.0 m/s c. 20.0 m/s d. 80.0 m/s e. none of the above

b. 5.0 m/s

A piece of putty and a rubber ball have the same mass. If you drop them from the same height, which object will produce a greater impulse and why? a. The silly putty will produce a greater impulse because it will bounce b. The rubber ball will produce a greater impulse because it will bounce c. The sill putty will produce a greater impulse because it will stop when it hits the ground d. The rubber ball will produce a greater impulse because it will stop when it hits the ground

b. The rubber ball will produce a greater impulse because it will bounce

A cannon recoils from launching a cannonball. The speed of the cannon's recoil is small because the a. impulse on the cannon is less than the impulse on the cannonball b. cannon has far more mass than the cannonball c. momentum of the cannon is unchanged d. force against the cannon is relative small e. none of the above

b. cannon has far more mass than the cannonbal

A cannonball shot from a long-barrel cannon travels faster than one short from a short-barrel cannon because the cannonball receives a greater a. force b. impulse c. both A and B d. neither A nor B

b. impulse

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 a. acceleration b. momentum c. speed d. all of the above e. none of the above

b. momentum

A moving freight car runs into an identical car at rest on the track. The cars couple together. Compared to the velocity of the first car before the collision, the velocity of the combined cars after the collision is a. zero b. one half as large c. the same d. twice as large e. more information is needed to say

b. one half as large

Suppose an astronaut in outer space wishes to toss a ball against a very massive as the astronaut, then a. the astronaut's time between catches will decrease as the game progresses b. the astronaut will never catch the first bounce c. the astronaut will catch one bounce only d. none of the above

b. the astronaut will never catch the first bounce

In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because a. the time of impact is decreased b. the time of impact is increased c. the velocity of the hand is reduced d. the momentum of impact is reduced e. none of the above

b. the time of impact is increased

2 kg ball is thrown at 3m/s. What is the ball's momentum? a. 2 kg*/s b. 3 kg*/s c. 6 kg*/s d. 9 kg*/s e. none of the above

c. 6 kg*/s

A table tennis ball moving forward with 5 units 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 5 units b. 5 units c. more than 5 units d. not enough information

c. more than 5 units

Suppose a cannon is made of a strong but very light material. Suppose also that the cannonball is more massive than the cannon itself. For such a system a. conservation of momentum would not hold b. conservation of energy would not hold c. the target would be safer place than where the operator is located d. the force on the cannonball would be greater than the force on the cannon e. recoil problems would be lessened

c. the target would be safer place than where the operator is located

Two gliders having the same mass and speed move toward each other on an air track and stick together. After the collision, the velocity of the gliders is a. twice the original velocity b. one half the original velocity c. zero d. the same as the original velocity e. there is not enough information to say

c. zero

A 5.0-kg chuck of putty moving at 10.0 m/s collides with and sticks to a 7.0-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 a. 0 kg*m/s b. 2.0 kg*m/s c. 15.0 kg*m/s d. 50.0 kg*m/s e. more than 50.0 kg*m/s

d. 50.0 kg*m/s

Which of the following has the largest momentum? a. A large truck parked in a parking lot b. A tightrope walker crossing Niagara Falls c. The science building at your school d. A pickup truck traveling down the highway e. A dog running down the street

d. 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 a. less stopping distance b. more momentum c. more mass d. all of the above e. none of the above

d. all of the above

A karate expert executes a swift blow and splits a cement block with her bare hand a. the forces on both the block and the expert's hand have the same magnitude b. the times of impact on both the block and the expert's hand are the same c. the impulses on both the block and the expert's hand have the same magnitude d. all of the above e. none of the above

d. all of the above

A fright train rolls along a track with considerable momentum. If it were to roll at the same speed, but had twice as much mass, its momentum would be a. zero b. unchanged c. quadrupled d. doubled

d. doubled

Momentum of a system is conserved only when a. there are no internal forces acting on the system b. the system is not moving c. there are no forces acting on the system d. there is no net external force acting on the system e. the system has zero momentum

d. there is no net external force acting on the system

Suppose a girl is standing on a pond where there is no friction between her feet and the ice. In order to get off the ice, she can a. bend over touching the ice in front of her and then bring her feet to her hands b. walk very slowly on tiptoe c. get on her hands and knees and crawl off the ice d. throw something in the direction opposite to the way she wants to go e. all of the above will work

d. throw something in the direction opposite to the way she wants to go

The reason padded dashboards are used in cars is that they a. look nice and feel good b. decrease the impulse in a collision c. increase the force of impact in a collision d. decrease the momentum of a collision e. increase the time of impact in a collision

e. increase the time of impact in a collision