Question

A rock is thrown straight up at 22.0 m/s from a roof of a 30.0 m tall building. After rising, the rock falls on the street below. Ignoring air resistance, how much time is the rock in the air?

Show the work please :)

Answer 1

hf=hi+vi*t-4.8t^2
4.8t^2-22t-30=0
use the quadratic equation to solve for time t.

Answer 2

5.59 seconds