Try This
Use the Collision Simulator to help you answer the following question. 

A 9.0-kg ball is travelling to the right at 8.0 m/s until it impacts a 3.0-kg stationary ball.  After the collision, the 9.0-kg ball is travelling at 5.61 m/s at an angle of 7.8º above the horizontal.  Calculate the velocity of the 3.0-kg ball after the impact. 


Read Collisions in Two Dimensions
Read Collisions in Two Dimensions on page 487 to Example 9.14 on page 495.  Also read Elastic and Inelastic Collisions in Two Dimensions on pages 495 to 498.

When you are finished, try questions 1-4 in 9.4 Check and Reflect on page 499.