In the following question, a statement of Assertion is followed by a statement of Reason. Mark the correct choice.
Assertion: In an elastic collision of two billiard balls are in contact with each other. During the short time of collision, kinetic energy is conserved.
Reason: Energy, spent against friction does not follow the law of conservation of energy

Options

A. Both assertion and reason are true and reason explains assertion correctly.
B. Both assertion and reason are true but reason does not explain assertion correctly
C. Assertion is true but reason is false
D. Assertion is false but reason is also false

Answer

D

Explanation

When the billiard balls are in an elastic collision, their total energy is partly kinetic and partly potential. Hence kinetic energy is less than total energy.
The energy, spent against friction is dissipated as heat. It is not available for doing work.