Question

A coin is dropped from a balloon going up with a uniform velocity of 12m/s. If the balloon was 81m height when the coin was dropped, find its height when the coin hits the ground. Tae the g = 10m/s2.

Answer 1

When the coin was dropped, the initial velocity of the coin is, u = 12 m/s (upward), acceleration due to gravity g = -10 m/s² (downward), height through which the coin has to fall, h = -86 m (downward)

Using,

S = ut + 1.2 at²

=> -86 = 12t – ½ × 10 × t²

=> t = 5.5 s

Now, the balloon was at height 86 m from the ground when the coin was dropped.

As the coin reaches the ground, the distance travelled by the balloon in this time = ut

= (12)(5.5) = 66 m

So, height of the balloon from the ground when the coin reaches the ground is = 86 + 66 = 152 m