Question

A ball is dropped from a balloon going up at a speed of $5m/s$. If the balloon was at a height $60$m at the time of dropping the ball, how long will the ball take to reach the ground?

Answer 1

$V_{b,g}=5m/s$ (velocity of ball w.r.t ground)

$H=60m$

$s=-ut-\frac{1}{2}g{t}^2$

$-60=-5t-5t^2$

$t^2+t-12=0$

$t^2+4t-3t-12=0$

$t(t+4)-3(t+4)=0$

$t=3s$