Question

a car 'A' of mass 1500 kg,travelling at 25m/s collides with another car 'B' of mass 1000 kgtravelling at 40m/s in the same direction.after collision,velocity of car 'A'becomes 20 m/s.find velocity of car 'B' after collision?

Answer 1

m1 = 1500kg
v1 = 25 m/s
m2 = 1000kg
v2 = 40 m/s

v3 = 20 m/s
v4 = ?

m1v1+m2v2 = m1v3+m2v4
(1500×25)+(1000×40) = (1500×20)+ 1000v4
(37500 + 4000) - 30000 = 1000v4
v4 = 11500/1000
v4 = 115/10
v4 = 11.5 m/s

Answer 2

m1 = 1500kg

v1 = 25 m/s

m2 = 1000kg

v2 = 40 m/s

v3 = 20 m/s

v4 = ?

m1v1+m2v2 = m1v3+m2v4

(1500×25)+(1000×40) = (1500×20)+ 1000v4

(37500 + 4000) - 30000 = 1000v4

v4 = 11500/1000

v4 = 115/10

v4 = 11.5 m/s