3.07 Quiz: Energy During Collisions

Two objects, A and B, each of mass 0.22 kg, are moving at 0.34 m/s directly toward each other. What is the speed of Object A after an elastic collision?

0.34 m/s

A 0.22 kg air-track glider moving at 0.60 m/s collides elastically into a 0.44 kg glider at rest. After collision the 0.22 kg glider is moving with velocity -0.20 m/s. What is the speed of the 0.44 kg glider after collision?

0.40 m/s

Two objects, A and B, each of mass 0.22 kg, are moving at 0.52 m/s directly toward each other. A completely inelastic collision occurs and both objects stop. What percentage of the total kinetic energy is changed into other forms of energy?

100%

Which of these is the best example of an elastic collision?

A billiard ball strikes another of the same mass at rest and stops, and the second ball then moves with the same velocity as the first ball. (Why: An elastic collision is one in which the total kinetic energy before and after the collision are equal. The kinetic energy is revealed to be the same because the second ball is moving at the same velocity as the first ball.

Which of these is true of an inelastic collision between two objects in a closed system but not of an elastic collision?

Kinetic energy is less after the collision.

Which of these is true about momentum and kinetic energy in a collision within a closed system?

Momentum is conserved, but total kinetic energy may or may not be conserved.