Find the time taken, by the body projected vertically up with a speed of u, to return back to the ground.

Explanation

Let us take the equation `S=ut + 1//2 at^(2)`
For entire motion `S=0`

`a=-g`
`u=u`
`O=ut -1//2 gt^(2)`
`1//2 gt^(2)= ut`
`t=2u//g`