A boy of mass `40 kg` is standing at one ned of the boat (mass : 80 kg) of length 6m in a river. Now the boy reaches to other end of the boat. Find the distance moved by the boat and the distance travelled by boy as seen from the bank of river.Assume that the system is at rest and no friction between the boat and the water.

Explanation

Since the location of c.m. is fixed , as the body moves towards the left , to keep the location of c.m. fixed , (boat + boy) move towards the right by `x`.
`40 xx 6 = (40 + 80)x rArr x = 2 m`
Distance travelled by the boy as seen from the bank is
`6 - 2 = 4m`