A 13,500 kg railroad freight car travels on a level track at a speed of 4.5 m/s. It collided and coupled with a 25,000 kg second car, initially at rest and with brakes released. What is the speed of the two cars after collision

Answer: 1.6m/s

Explanation:

M1 = 13500kg

U1 = 4.5m/s

M2 = 25000kg

U2 = 0m/s (since the body is at rest)

V = ? (Common velocity or velocity after impact)

M1U1 + M2U2 = (M1 + M2) V

But U2 = 0

M1U1 = (M1 + M2) V

13500 * 4.5 = (13500 + 25000) v

60750 = 38500v

V = 60750 / 38500 = 1.5779 = 1.6m/s