Unit 2B Quiz 2 Conservation of Linear Momentum & Collisions

Which of the following statements best describes the principle of conservation of linear momentum?

• The total momentum of a closed system is constant unless an external force acts on the system.
• The total kinetic energy of a closed system is constant unless an external force acts on the system.
• The total potential energy of a closed system is constant unless an external force acts on the system.
• The total mechanical energy of a closed system is constant unless an external force acts on the system.

In a perfectly elastic collision, what happens to the total kinetic energy of the colliding objects?

• It stays the same.
• It increases.
• It decreases.
• It is converted to potential energy.

Which of the following best describes an inelastic collision?

• Kinetic energy is conserved, but momentum is not.
• Momentum is conserved, but kinetic energy is not.
• Neither kinetic energy nor momentum is conserved.
• Both kinetic energy and momentum are conserved.

In an inelastic collision, what happens to the total mechanical energy of the system?

• It is conserved.
• It is converted to thermal energy.
• It is converted to potential energy.
• It is increased.

Which of the following is true about the conservation of momentum in a closed system?

• Momentum is always conserved.
• Momentum is only conserved in elastic collisions.
• Momentum is only conserved in inelastic collisions.
• Momentum is only conserved if no external forces act on the system.

Two objects of equal mass collide head-on. If the collision is perfectly elastic, what is the final velocity of the objects after the collision?

• They come to rest.
• They continue in the same direction at their original velocities.
• They continue in opposite directions at their original velocities.
• They continue in opposite directions, exchanging velocities.

In an elastic collision between two objects, the total kinetic energy of the system is:

• Always conserved.
• Never conserved.
• Only conserved if the masses of the objects are equal.
• Only conserved if the velocities of the objects are equal.

A 2 kg object moving at 10 m/s collides with a 3 kg object moving at 5 m/s in the opposite direction. If the collision is perfectly inelastic, what is the final velocity of the combined objects?

• 0 m/s
• 2.5 m/s
• 5 m/s
• 7.5 m/s

What is the principle of conservation of linear momentum in a closed system?

• Momentum before collision equals momentum after collision.
• Total energy remains constant within a closed system.
• External net force equals mass times acceleration in an open system.
• Velocity remains unchanged for all objects in a closed system.

In an elastic collision, which of the following statements is true?

• Kinetic energy is conserved.
• Momentum is not conserved.
• Objects stick together after collision.
• Heat (or thermal energy) is generated.