a particle of mass 5m moving with speed v, explodes and splits into two pieces with masses of 2m and 3m. The lighter piece continues to move in the original direction with speed v relative to the heavier piece. What is the speed of the lighter piece

Answer 1

The total momentum remains 5m*v in the forward direction.
Heavier piece speed after breakup = v1
Lighter piece speed after breakup = v2
v2 - v1 = v

5mv = 2m*v2 + 3m*v1
= 2m*v2 + 3m*(v2 - v)
8*mv = 5*mv2

v2 = (8/5)v
v1 = (3/5)v
The lighter piece moves faster.