Physics chapter 8/9 conseptuals

In a collision between two objects having unequal masses, how does magnitude of the impulse imparted to the lighter object by the heavier one compare with the magnitude of the impulse imparted to the heavier object by the lighter one? A)Both objects receive the same impulse. B)The lighter object receives a larger impulse. C)The heavier object receives a larger impulse. D)The answer depends on the ratio of the masses. E)The answer depends on the ratio of the speeds.

A

As a tile falls from the roof of a building to the ground its momentum is conserved. A)True B)False

B

When you ride a bicycle, in what direction is the angular velocity of the wheels? A)up B)forwards C)backwards D)to your left E)to your right

D

A horizontal disk rotates about a vertical axis through its center. Point P is midway between the center and the rim of the disk, and point Q is on the rim. If the disk turns with constant angular velocity, which of the following statements about it are true?(There may be more than one correct choice.) A)The linear acceleration of P is twice as great as the linear acceleration of Q. B)The angular velocity of Q is twice as great as the angular velocity of P. C)Q is moving twice as fast as P. D)The linear acceleration of Q is twice as great as the linear acceleration of P. E)P and Q have the same linear acceleration.

C,D

A baseball is thrown vertically upward and feels no air resistance. As it is rising A)both its momentum and its kinetic energy are conserved. B)both its momentum and its mechanical energy are conserved. C)its kinetic energy is conserved, but its momentum is not conserved. D)its gravitational potential energy is not conserved, buts its momentum is conserved. E)its momentum is not conserved, but its mechanical energy is conserved.

E

A small glider is coasting horizontally when suddenly a very heavy piece of cargo falls out of the bottom of the plane. You can neglect air resistance. Just after the cargo has fallen out A)the plane speeds up but the cargo does not change speed. B)both the cargo and the plane speed up. C)the plane speeds up and the cargo slows down. D)the cargo slows down but the plane does not change speed. E)neither the cargo nor the plane change speed.

E

As you are leaving a building, the door opens outward. If the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it? A)forwards B)to your left C)up D)to your right E)down

E

In an INELASTIC collision between two objects A)the momentum of each object is conserved. B)the kinetic energy of each object is conserved. C)the kinetic energy of the system is conserved, but the momentum of the system is not conserved. D)both the momentum and the kinetic energy of the system are conserved. E)the momentum of the system is conserved but the kinetic energy of the system is not conserved.

E

A small car has a head-on collision with a large truck. Which of the following statements concerning the magnitude of the average force due to the collision is correct? A)The small car and the truck experience the same average force. B)The truck experiences the greater average force. C)The small car experiences the greater average force. D)It is impossible to tell since the masses are not given. E)It is impossible to tell since the velocities are not given.

A

On a smooth horizontal floor, an object slides into a spring which is attached to another mass that is initially stationary. When the spring is most compressed, both objects are moving at the same speed. Ignoring friction, what is conserved during this interaction? A)momentum and mechanical energy B)momentum and potential energy C)kinetic energy only D)momentum only E)momentum and kinetic energy

A

A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring A)the heavier block will have more kinetic energy than the lighter block. B)the lighter block will have more kinetic energy than the heavier block. C)both blocks will have equal speeds. D)both blocks will both have the same amount of kinetic energy. E)the magnitude of the momentum of the heavier block will be greater than the magnitude of the momentum of the lighter block.

B

In a perfectly ELASTIC collision between two perfectly rigid objects A)the kinetic energy of each object is conserved. B)both the momentum and the kinetic energy of the system are conserved. C)the momentum of each object is conserved. D)the momentum of the system is conserved but the kinetic energy of the system is not conserved. E)the kinetic energy of the system is conserved, but the momentum of the system is not conserved.

B

There must be equal amounts of mass on both side of the center of mass of an object. A)True B)False

B

When a rigid body rotates about a fixed axis, all the points in the body have the same A)centripetal acceleration. B)angular acceleration. C)tangential acceleration. D)linear displacement. E)tangential speed.

B

You are standing on a skateboard, initially at rest. A friend throws a very heavy ball towards you. You can either catch the object or deflect the object back towards your friend (such that it moves away from you with the same speed as it was originally thrown). What should you do in order to MINIMIZE your speed on the skateboard? A)Deflect the ball. B)Catch the ball. C)Your final speed on the skateboard will be the same regardless whether you catch the ball or deflect the ball.

B

1)Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greatest impact force? A)hitting the brick wall B)hitting the other car C)The force would be the same in both cases. D)We cannot answer this question without more information. E)None of these is true.

C

A shell explodes into two fragments, one fragment 25 times heavier than the other. If any gas from the explosion has negligible mass, then A)the kinetic energy change of the heavier fragment is 25 times as great as the kinetic energy change of the lighter fragment. B)the momentum change of the lighter fragment is 25 times as great as the momentum change of the heavier fragment. C)the momentum change of the lighter fragment is exactly the same as the momentum change of the heavier fragment. D)the kinetic energy change of the lighter fragment is 25 times as great as the kinetic energy change of the heavier fragment. E)the momentum change of the heavier fragment is 25 times as great as the momentum change of the lighter fragment.

C