Free fall Question

a. Take upward be positive

Displacement, s = 0.5 m

At the maximum height, v = 0

Acceleration due to gravity, a = -10 ms-2

So, v2 = u2 + 2as

0 = u2 + 2(-10)(0.5)

u = 3.16 ms-1

So, the jumping speed of the boy is 3.16 ms-1

By s = ut + 1/2 at2

0 = (3.16)t + 1/2 (-10)t2

5t2 – 3.16t = 0

t = 0 (rejected) or 0.632 s

So, the hang-time of the boy is 0.632 s.