A ball is dropped from a balloon going up at a speed of 7 m/s. If the balloon was at a height 60 m at the time of dropping the ball, how long will the ball take in reaching the ground?

Options

A. `8 m`
B. `12 m`
C. `18 m`
D. `24 m`

Answer

C

Explanation

`s=ut+(1)/(2)at^(2)=4xx5-(1)/(2)xx9.8xx5^(2)=20-122.5=-102.5 m`
This shows that body is `102.5 m` below the initial position, i.e. height of the body `=120.5 -1002.5 =18 m` .