A railway truck of mass 800 kg moving with a constant velocity of 5 m/s, collides and couples

with another railway truck of mass 6+50 kg

which is stationary. Calculate the common velocity (v) with which the coupled trucks move off

after the collision.

The common velocity of truck v = 2.759 m/s

Explanation:

Given that,

Mass of first railway truck, M = 800 Kg

Mass of second railway truck, m = 650 Kg

Velocity of first railway truck, U = 5 m/s

Velocity of second truck, u = 0 m/s

According to the conservation of linear momentum,

The total momentum after impact = total momentum before impact

The mass of the truck remains the same, but the velocity after impact is coupled to be v.

Therefore,

Mv + mv = MU + mu

v (M+m) = MU (u = 0)

v = MU / (M+m)

Substituting the values in the above equation,

v = 800 Kg x 5 m/s / (800 Kg + 650 Kg)

v = 2.759 m/s

Hence, the common velocity of the coupled tucks moving off after collision is v = 2.759 m/s