a 1.5 kg blue ball moves with a speed of 2.5 m/s collides, another 1.5 kg red ball which is at rest. after collision, the blue ball moves off at an angle of 30 deggress to the original direction of motion and the red ball deflects at an angle of theta to the same axis. find the final velocity of each ball and the angle?

Question

Steve · Accepted Answer

Without loss of generality, we may assume that the 1st ball is moving in the +x direction.

After the collision, since the two balls are identical, the resultant v1+v2 will still have the same direction, which means that the two velocities are both 30° from the original v, in opposite directions.

So, one moves at an angle of +30° and the other at an angle of -30°

Now just work out the x- and y-components.