Question

A ball falls 20meters from rest to the ground below

a)What is the velocity as it strikes the ground?

b)How long does it take to fall?

Answer 1

(a)

$$v=\sqrt{2gh}=\sqrt{2*9.8*20}=19.8\:\rm m/s$$

(b)

$$t=\frac{v}{g}=\frac{19.8}{9.8}=2.0\:\rm s$$