Posted by Taylor on .
A 0.060kg tennis ball, moving with a speed of 5.8m/s, has a headon collision with a 0.10kg ball initially moving in the same direction at a speed of 2.8m/s.
Assuming a perfectly elastic collision, determine the speed of each ball after the collision.
Determine the direction of tennis ball after the collision.
Determine the direction of 0.10kg ball after the collision.

UPhys 
bobpursley,
Use the conservation of momemtum first.
solve for the veloicity of the tennis ball in terms of the other items. Put that expression into the Conservation of KEnergy equation, then solve the quadratic equation.
I will be happy to crititque your work.