Question

A balloon tied up with a wooden piece is moving upward with velocity of 15m/s. At a height of 300m above the ground, the wooden block detached from the balloon. How much time will it take to reach the ground?

Answer 1

Assume the wooden piece prevents the balloon from rising, is not so heavy as to cause the balloon to descend. and the 15 m/s is horizontal velocity “riding the wind,” That horizontal velocity does not affect the time the wood will take to reach the ground after release. Initial vertical velocity is zero.

s = u t + 1/2 g t^2

s is the height above ground, 300 m.

u is initial vertical velocity, zero.

t is time to reach the ground.

g is acceleration of gravity near Earth, 9.8 m/s^2.

300 m = 0 t + 1/2 (9.8 m/s^2) t^2

300 m = (4.9 m/s^2) t^2

61.22 s^2 = t^2

7.82 seconds = t