A truck of mass 4×10^3 moving at 3.5 ms^-1 collides with a stationary truck to which it becomes automatically coupled. Immediately after the impact the trucks moves along together at 2 ms^-1 in the same direction. Find the mass of the second truck.

Answer 1

M1*V1 + M2*V2 = M1*V + M2*V.
4000*3.5 + M2*0 = 4000*2 + M2*2
14,000-8000 = 2M2
M2 = 3,000 kg.