Car A of mass 1500 kg travelling at 25 m/s collides with another car B of mass 1000 kg travelling at 15 m/s in the same direction. After collision, the velocity of car A becomes 20 m/s. Calculate the velocity of car B after collision.

Apparently this has been asked a few years ago, so I copied this answer from deepikakvvk06 - - all credit goes to them!

velocity of car 'B' after collision is 22.5m/s. //it's a conservation of momentum question

Explanation:

Let ,

mass = m

initial velocity = u

final velocity = v

here ,

m₁= 1500 kg

m₂=1000 kg

u₁ = 25 m/s

u₂ = 15 m/s

v₁ = 20 m/s

we have to find v₂ !!

v₂ is the velocity after collision

Here is a formula relating the values given ,

m₁u₁+m₂u₂ = m₁v₁ + m₂+v₂

m₁u₁+m₂u₂ = 1500 × 25 + 1000 ×15

= 37500 + 15000

= 52500

m₁v₁ + m₂+v₂ = 1500 × 20 + 1000 × v₂

= 30000 + 1000v₂

m₁u₁+m₂u₂ = m₁v₁ + m₂+v₂

52500 = 3000 + 1000v₂

1000v₂ = 52500 - 30000

1000 v₂ = 22500

v₂ = 22500/1000

= 22.5 m/s

Thus, velocity of car 'B' after collision is 22.5m/s.

a displacement distance is size of displ

distance = 150m

displ = root (50 ^2 + 100^2)

root(2500+10000)

root 125000