Question

A ball is dropped from a height of 19.6 m (g = 9.8 ms⁻²)
(i) How long does it take to hit the ground ?
(ii) With what velocity does it hit the ground?

Answer 1

We can find the solution by the use of the Equations of motion.

Answer 2

Time taken to hit the ground = 2 seconds

Final velocity = 19.6 m/s

Explanation:

Given: Ball is dropped from a height of 19.6 m

g = 9.8 ms⁻²

(i) Distance = 19.6 m

Initial velocity u = 0

gravity g = 9.8 m/s2

s = ut + 1/2 at^2

19.6 = 1/2 * 9.8 * t2

19.6 * 2 / 9.8 = t^2

t^2 = 4

So t = root of 4 = 2 seconds.

(ii) Final velocity v

v = acceleration * time = 9.8 * 2 = 19.6 m/s