Question

A man in a balloon throws a stone downwards with a speed of $5\, m s^{-1}$ with respect to the balloon which is moving upwards with a constant acceleration of $5 \, ms ^{-2}$. Find the magnitude of velocity (in $m s^{-1}$ ) of the stone relative to the man after $2\, s$. (Take $g=10\, ms ^{-2}$ )

Answer 1

Initial relative velocity of stone wrt man $=5\,ms^{- 1}$
relative acceleration of the stone wrt man $=\left(- 10\right)-\left(\right.5\left.\right)=-15\,ms^{- 2}$
$v=u+at=5-15\times 2=-25\,ms^{- 1}$
Magnitude of relative velocity after $t=2s$ is $25\,ms^{- 1}​$