girl of mass 40kg having v 2m/s jumps on a stationary cart of mass 4 kg find the velocity of girl when the cart starts moving

Answer 1

M1*V1 + M2*V2 = M1*V + M2*V
40*2 + 4*0 = 40V + 4V
44V = 80
V = 1.82 m/s.