Question

A balloon is rising vertically up with a velocity of $29\, ms ^{-1}$. A stone is dropped from it and it reaches the ground in $10$ seconds. The height of the balloon when the stone was dropped from it, was $\left( g =9.8 \,ms ^{-2}\right)$

• A. 100 m
• B. 200 m
• C. 400 m
• D. 150 m

Answer 1

Answer: (B)

For stone to be dropped from rising balloon of velocity $29 \,m / s$,
$u =-29 \,m / s , t =10 \,sec$.
$\therefore h = -29 \times 10 + \frac{1}{2} \times 9.8 \times 100$
$ = - 290 + 490 = 200\,m$