Given m1 = 0.05kg, u1 = 200ms−1, m2 = 0.95kg
K.E = 12mrv2
m1u1 = v(m1 + m2) [law of conversation of momentum]
v = 0.05×2000.05+95 = 10ms−1
K.E = 12(1)102 = 50J