If two carts collide, what type of collision will conserve both momentum and kinetic energy?

a. head on

b. perfectly inelastic

c. none

d. perfectly elastic

The appropriate answer is d. perfectly elastic. When a perfectly elastic collision occurs both momentum and kinetic energy are preserved. Momentum is the mass of an object times its velocity while kinetic energy is the energy that a moving object has due to its motion. In an elastic collision kinetic energy would be converted to some other form of energy.