Question

A rock,thrown straight up, takes 4.2 seconds to reach its max height (g=9.8m/s) what was the initial velocity? what was its maximum height?

Answer 1

Known data:

time=4,2s

Earth's acceleration:9.8m/s²

Formulas needed:

t=v÷g

S=vt+(gt²)÷2

Solution:

t=v÷g

4,2=v÷9,8

v=9,8×4,2

v=41,16m/s

S=vt+(gt²)÷2

S=41,16×4,2-9.8×(4,2)²÷2

S=86.436m