You just have to use both momentum and energy equations, and do the messy algebra. Two equations, two unknowns (the two ball velocities after collision).
Enjoy the messy algebra.
A 550-g ball traveling at 8.0 m/s undergoes a head-on elastic collision with a 250-g ball traveling toward it also at 8.0 m/s. What is the speed of the 250-g mass after the collision?
2 answers
16 m/s