posted by Trouble .
A ball with mass m = 0.210 kg and kinetic energy K1 = 2.97 J collides elastically with a second ball of the same mass that is initially at rest. After the collision, the first ball moves away at an angle of = 30.6° with respect to the hori- zontal, as shown in the figure. What is the kinetic energy of the first ball after the collision?
Please step by step
I only got the the first V of M1 that it is 5.31 m/s :/