Someone. problem:

starting with an initial speed of 5.00 m/s at a height of h = 0.260 m, the m1 = 1.55 kg ball swings downward and strikes the m2 = 4.50 kg ball that is at rest, as the drawing shows.

(a) using the principle of conservation of mechanical energy, find the speed of the 1.55-kg ball just before impact.
(b) assuming that the collision is elastic, find the velocities (magnitude and direction) of both balls just after the collision.
(c) how high does each ball swing after the collision, ignoring air resistance?