Title: multiple choice
Course: Physics copy 1

Q: A baseball of mass m leaves a pitching machine of mass M (Where M includes the mass of the ball m) with a speed of v. The recoil speed of the machine after shooting the baseball it
- 2mv/(M-m)
- mv/M
- mv/(M + m)
- mv/(M + m)
- 0
A: mv/(M + m)

Q: A glider of mass m travels leftward on a frictionless air track with a speed v. It collides head-on in a completely inelestic collission with a glider that has twice its mass and half its speed moving to the right. After the collision, the combined speed of the glider system is
- 0
- v/3
- v/2
- 2v
- v
A: 0

Q: A rubber bullet R and a metal bullet M of equal mass strike a test target T with the same speed. The metal bullet penetrates the target and comes to rest inside it, while the rubber bullet bounces off the target. Which statement is true?
- M and R exert the same impulse of T
- M exerts a greater impulse on T than R does
- R exerts a greater impulse on T than M does
- The magnitudes of the change in momentum of M and R are equal
- none of these
A: R exerts a greater impulse on T than M does

Q: If an arrow's speed and mass are both doubled, then its momentum and kinetic energy are respectively increased by factors of
- 2 and 2
- 2 and 4
- 4 and 4
- 4 and 8
- 8 and 8
A: 4 and 8

Q: In an inelastic collission involving two interacting objects, the final kinetic energy of the system
- can be equal to the initial kinetic energy of the system
- is always less than or equal to the initial kinetic energy of the system
- is always greater than or equal to the initial kinetic energy of the system
- is always less than the initial kinetic energy of the system
- can be greater than the initial kinetic energy of the system
A: is always less than or equal to the initial kinetic energy of the system

Q: The area under the line on a force-time graph indicates
- the impulse
- the change in momentum
- the product of the average force and the time interval during which that force is applied
- all of these
- none of these
A: all of these

Q: The force applied by an apple hitting the ground depends on:
- whether or not the apple bounces
- the time interval of the impact with the ground
- the apple's maximum speed just before impact
- the air resistance acting on the apple as it falls
- all of these
A: all of these

Q: Two protons approach one another is a straight line with equal speeds. Eventually, they repel, and move apart with equal speeds in the same straight line. At the instant of minimum separation between the particles
- the total momentum of the interacting particles drops to zero, but the total energy of the system remains constant
- both the total momentum and the total energy drop to zero
- the total momentum of the system is at the maximum value, but the total energy drops to zero
- both the total momentum and the total energy of the system are at their maximum values
- both the total momentum and the total energy of the system are reduced, but not to zero
A: the total momentum of the interacting particles drops to zero, but the total energy of the system remains constant

Q: Using L, M, and T for the dimensions of length, mass, and time, respectively, the dimensions of impulse are
- LT/M
- L/TM
- ML^2/T^2
- ML/T^2
- ML/T
A: ML/T

Q: When you are jogging and you increase your kinetic energy by a factor of 2, then your momentum
- changes by a factor of ½
- increases by a factor of 2
- increases by a factor of 4
- increases by an amount that cannot be determined with the information given
A: increases by an amount that cannot be determined with the information given

Q: When you catch a fast-moving baseball, your hand hurts less if you move it in the same direction as the ball because
- the change in momentum in the ball is less
- the change in kinetic engergy of the ball is less
- the time interval of the interaction is less
- the time interval of the interaction is greater
- the impulse on the ball is greater
A: the time interval of the interaction is greater

Q: A 10 000 kg freight car moving at 2 m/s collides with a stationary 15 000 kg freight car. The two cars couple and move off at:
- 0.8 m/s
- 1 m/s
- 1.33 m/s
- 2 m/s
A: 0.8 m/s

Q: A 30-kg girl and a 25-kg boy face each other on frictionless roller skates. The girl pushes the boy, who moves away at a speed of 1.0 m/s. The girl's speed is
- 0.45 m/s.
- 0.55 m/s.
- 0.83 m/s.
- 1. 2 m/s.
A: 0.83 m/s.

Q: A ball whose momentum is p strikes a wall and bounces off. The change in the ball's momentum is:
- 0.
- p/2.
- p.
- 2p.
A: 2p.

Q: An astronaut whose total mass is 100 kg ejects 1.0 g of gas from his propulsion pistol at a speed of 50 m/s. His recoil speed is:
- 0.5 mm/s
- 5 mm/s
- 5 cm/s
- 50 cm/s
A: 0.5 mm/s

Q: An elastic collision conserves:
- kinetic energy but not momentum.
- momentum but not kinetic energy.
- neither momentum nor kinetic energy.
- both momentum and kinetic energy.
A: both momentum and kinetic energy.

Q: An iron sphere of mass 30 kg has the same diameter as an aluminum sphere of mass 10. 5 kg. The spheres are simultaneously dropped from a cliff. When they are 10 m from the ground, they have identical
- accelerations.
- momenta.
- potential energies.
- kinetic energies.
A: accelerations.

Q: An object at rest may possess:
- velocity
- momentum.
- kinetic energy.
- potential energy.
A: potential energy.

Q: An object in motion need not possess:
- velocity.
- momentum
- kinetic energy.
- potential energy
A: potential energy

Q: An object which has momentum must also have:
- acceleration.
- impulse
- kinetic energy
- potential energy
A: kinetic energy

Q: If a rocket of initial mass m is to rise from its launching pad, its initial thrust must exceed
- 1/2 mg
- mg
- 2 mg.
- 12 mg
A: mg

Q: If a shell fired from a cannon explodes in midair:
- its total momentum increases.
- its total momentum decreases.
- its total kinetic energy increases.
- its total kinetic energy decreases.
A: its total kinetic energy increases.

Q: Momentum is most closely related to:
- kinetic energy.
- potential energy.
- impulse.
- power.
A: impulse.

Q: The average momentum of a 70-kg runner who covers 400 m in 50 s is:
- 8.75 kg-m/s.
- 560 kg-m/s.
- 57 kg-m/s.
- 5488 kg-m/s.
A: 560 kg-m/s.

Q: The impulse given to an object is equal to the consequent change in:
- velocity.
- momentum.
- kinetic energy.
- potential energy.
A: momentum.

Q: The moving object A collides elastically with the stationary object B. The energy transfer to B is greatest when:
- mB is greater than mA.
- mB is equal to mA.
- mB is less than mA.
- any of the above occur, depending on the circumstances.
A: mB is equal to mA.

Q: What never changes when two or more objects collide is:
- the momentum of each one.
- the kinetic energy of each one.
- the total momentum of all the objects.
- the total kinetic energy of all the objects.
A: the total momentum of all the objects.

Q: When the velocity of a moving object is doubled:
- its acceleration is doubled.
- its momentum is doubled.
- its kinetic energy is doubled.
- its potential energy is doubled.
A: its momentum is doubled.