Question

A steel ball A of mass 20.0 kg moving with a speed of 2.0 ms−1
collides with another
ball B of mass 10.0 kg which is initially at rest. After the collision A moves off with a
speed of 1.0 ms−1
at an angle of 30º with its original direction of motion. Determine the
final velocity of B.

Answer 1

assign the initial path of A as either the x or y direction

find the initial momentum of A in the x and y directions
... then, find the final momentum of A in the x and y directions
... the difference, in x and in y, is the momentum imparted to B

use B's x and y momenta to find its final velocity