Question

A man of $80 \, kg$ attempts to jump from a small boat of mass $40 \, kg$ on to the shore. He can generate a relative velocity of $6 \, m \, s^{- 1}$ between himself and the boat. His velocity towards the shore is

• A. $4ms^{- 1}$
• B. $8ms^{- 1}$
• C. $2ms^{- 1}$
• D. $3ms^{- 1}$

Answer 1

Answer: (C)

Let the velocity of boat be $V$ opposite to the man. By momentum conservation, $-40V+80\left(\right.6-V\left.\right)=0$
$\therefore \, V=4ms^{- 1}$
$\therefore \, $ Velocity of the man $=6-4=2ms^{- 1}$