Question

Answer carefully, with reasons :

(a) In an elastic collision of two billiard balls, is the total kinetic energy conserved during the short time of collision of the balls (i.e. when they are in contact)?
(b) Is the total linear momentum conserved during the short time of an elastic collision of two balls?
(c) What are the answers to (a) and (b) for an inelastic collision?
(d) If the potential energy of two billiard balls depends only on the separation distance between their centres, is the collision elastic or inelastic?

Answer 1

Explanation:

a.) The initial and the final kinetic energy is equal in an elastic collision. When the two balls collide, there is no conservation of kinetic energy. It gets converted into potential energy.

b.)  The total linear momentum of the system is conserved in an elastic collision.

c.)  There will be a loss of kinetic energy in an inelastic collision. The K.E after the collision is always less than the K.E before the collision.

    The total linear momentum of the system is conserved in an inelastic collision also.

d.)  It is an elastic collision as the forces involved are conservative forces. It depends on the distance between the centres of the billiard balls.