Vertical Motion and Free Fall Video Lessons

Concept

# Problem: A football is kicked straight up into the air; it hits the ground 4.4s later. (a) What was the greatest height reached by the ball?(b)  Assume it is kicked from ground level. With what speed did it leave the kicker's foot?

###### FREE Expert Solution

Time to reach maximum height = T/2 = 4.4/2 = 2.2 s

(a)

Maximum height, Hmax

$\begin{array}{rcl}{\mathbf{H}}_{\mathbf{m}\mathbf{a}\mathbf{x}}& \mathbf{=}& \frac{\mathbf{1}}{\mathbf{2}}\mathbf{g}{\mathbf{t}}^{\mathbf{2}}\\ & \mathbf{=}& \frac{\mathbf{1}}{\mathbf{2}}\mathbf{\left(}\mathbf{9}\mathbf{.}\mathbf{81}\mathbf{\right)}{\mathbf{\left(}\mathbf{2}\mathbf{.}\mathbf{2}\mathbf{\right)}}^{\mathbf{2}}\end{array}$

###### Problem Details

A football is kicked straight up into the air; it hits the ground 4.4s later.

(a) What was the greatest height reached by the ball?

(b)  Assume it is kicked from ground level. With what speed did it leave the kicker's foot?