A `10 kg` boy standing in a `40 kg` boat floating on water is `20 m` away from the shore of the river. If the boy moves `8 m` on the boat towards the shore, then how far is he from the shore ? (Assume no friction between boat and water).

Explanation

Mass of the boy `(m)=10 kg` Mass of the boat `(M)=40 kg` Distance travelled by boy `(l)=8 m` Distance travelled by the boat in opposite direction `=(ml)/(M+m)=(10xx8)/(10+40)=1.6 m`
Distance of the boy from the shore is
`(20-8)+(1.6)=13.6 m`