Coefficient of restitution in rotation motion

[iitjee10]

Homework Statement

Suppose A ball of mass m moving with a speed v collides with a rod of mass M and length L placed horizontally on a smooth floor. The coefficient of restitution is 0.5.

Homework Equations

The Attempt at a Solution

In this case how do we utilise the information of COR.

If it were given COR is 1 then we could conserve kinetic energy. But in this case how do we how about it?

 

[fluidistic]

According to wikipedia the coefficient of restitution is worth $$\frac{v_{2f}-v_{1f}}{v_{1}-v_2}$$. (http://en.wikipedia.org/wiki/Coefficient_of_restitution) so it might be helpful.