# A ball with a mass of #2 kg# is rolling at #3 m/s# and elastically collides with a resting ball with a mass of #4 kg#. What are the post-collision velocities of the balls?

##### 1 Answer

#### Answer:

Speed of moving ball after collision

Speed of resting ball after collision

#### Explanation:

Apply conservation of linear momentum

Didvide both sides by

Now, use formula of coefficient of restitution (

#e = (v_2 - v_1)/(u_1 - u_2)#

For an elastic collision

Add equations

Substitute