" luction: "quad (2.1" ELASTICITY ")/(3)

(a) What is elastic potential energy of a spring ? Obtain the relation for elastic P.E. U=(1)/(2)kx^(2) . Where k is force constant of spring, x is extension or compression produced in the spring.

Two perfectly elastic balls of same mass m are moving with velocities u_(1) and u_(2) . They collide elastically n times. The kinetic energy of the system finally is:

A body of mass m1 collides head on perfectly elastically with a stationary body of mass m_(2) . If velocities of m_(1) before and after the collision are v and –v/3 respectively then the value of m_(1)//m_(2) is-