# Elastic Collisions

1. Feb 21, 2010

1. The problem statement, all variables and given/known data
Consider a pool table that contains two identical balls. Ball 1 is rolling at a speed of 1.1 m/sec when it hits ball 2 which is at rest. The coefficients of friction between the balls and the table are 0.8 (potential) and .5 (kinetic). The collision is perfectly elastic and there is no friction between the balls. How far will ball 2 skid before it is rolling without sliding.

2. Relevant equations
Speed - (Friction * Kinetic Energy)

3. The attempt at a solution
This seems rather simple, but I would like to check my work. Simply I need to find when the ball has overcome the force of friction, so wouldn't it be,
1.1 (velocity) - 9.8(friction) * .5 (kinetic energy) = 0?

if so that would turn out to be

t = 1.1/4.9 = .22 seconds

putting that back into the equation

1.1 = 4.9 * (.22) = .022 m

I am not quite sure if this is the correct approach to this problem, so help would be appreciated. Thanks in advance.