# An object is thrown vertically from a height of 2 m at 21 m/s. How long will it take for the object to hit the ground?

Mar 6, 2018

$0.092 s$

#### Explanation:

Let's find the velocity with which it will hit the ground,applying

${v}^{2} = {u}^{2} + 2 g s$

Given, $u = 21 m {s}^{-} 1 , s = 2 m$

So, v^2=21×21 +2×9.8×2

So, $v = 21.92 m {s}^{-} 1$

Now,if it took time $t$ in gaining that much velocity we can use, $v = u + g t$

So, $21.92 = 21 + 9.8 t$

Or, $t = 0.092 s$