Please if you Are smart with PHYSICS, please show me how to do problem?

Question

Stephanie hits a volleyball from a height of 0.80 m and gives it an inital velocity of +7.5m/s straight up.

A. How high wil the volleyball go?
B. how long will it take the ball to reach its maximum height?(hint: at maximum height, v=0m/s.

Answer 1

It does not always need smartness to solve this kind of problem. However, one needs to understand PHYSICS.

As hinted, v = 0 at the maximum height, and you know that only gravity would slow/ stop the upward movement. Thus: (B) The time took for the volleyball to reach the maximum height is t = 7.5/g = 7.5/9.81 (s) =
(A) The maximum height is therefore 0.5*g*t^2 = 0.5*(gt)^2/g = 0.5*(7.5)^2/9.81 (m) =