A cart of mass 50 kg is moving on a straight track with a speed of 12 m/s. A mass of 10 kg is gently put into the cart. What will be the velocity of the cart after this?
Since there is no external forces acting on the system using the conservation of momentum:
Initial momentum = final momentum
m1 = 50kg
m2 = 50+10 = 60kg
V1 = 12kg
V2 = ??
`m1V1 = m2V2`
`50xx12 = (50+10)V2`
`V2 = (50xx12)/60`
`V2 = 10`
So the velocity of the cart after this is 10m/s.