Question

a car of mass 1000 kg moving with a speed of 30 m/s collides with a back of a stationary bidy of mass 9 tonnes. Calculate the speed of vehicle immediately after collision if they remain together

Answer 1

According to the law of conservation of momentum,

m₁u₁ + m₂u₂ = (m₁ + m₂)v

where
m₁ = mass of the car = 1000 kg
m₂ = mass of the body = 9000 kg
u₁ = initial velocity of the car = 30 m/s
u₂ = initial velocity of the body = 0 m/s
v = velocity of the car and body combined together, after collision.

v = (m₁u₁ + m₂u₂ )/(m₁ + m₂)
= (1000 x 30 + 9000 x 0)/(1000 + 9000)
= 30,000/10,000
= 3 m/s.