# If a rock has a speed of 12 m/s as it hits the ground, from what height did it fall, assuming its initial speed was zero?

## Its mass is 50 kg.

Apr 11, 2018

To find the height the following formula should be used: ${v}^{2} = {u}^{2} + 2 a H$

#### Explanation:

Assuming this occurs on earth, $a = 9.8$ $m {s}^{-} 2$

${12}^{2} = {0}^{2} + 2 \times 9.8 \times H$

$\frac{144}{2 \times 9.8} = H$

$H = 7.35$ $m$