4) physics question..?

Question

Leonard throws a stone from the ground to the top of the school's flag pole, if it returns to the ground after 4 sec. . what is the height of the flag pole?

Answer 1

Let g be the acceleration due to gravity.

The speed at the highest point is 0.

If t is the time of upward flight:

0 = u - gt

u = 9.81 * 2

= 19.6 m/s.

At the highest point:

0^2 = u^2 - 2gh

h = u^2 / (2g)

= 19.6^2 / (2 * 9.81)

= 19.6 m.