Answer to Question #77676 in Physics for aesha

Question

Two identical balls traveling parallel to the x-axis have speeds of 30 cm/s and are oppositely directed. They collide perfectly elastically. After collision, one ball is moving at an angle of 30°; above the +x-axis. Find its speed and the velocity of the other ball.
Am I supposed to take the angle 30 into consideration while doing the calculations?

Answer 1

When two identical balls have equal speeds and are oppositely directed collide perfectly elastically their final speeds will be the same.
v_1=30 cm/s.
From the conservation of momentum:
v_2=30 cm/s.
The second ball is moving at an angle of 30° below the -x-axis.