Gravitational Potential Energy Video Lessons

Concept

# Problem: An impala is an African antelope capable of a remarkable vertical leap. In one recorded leap, a 45 kg impala went into a deep crouch, pushed straight up for 0.21 s, and reached a height of 2.5 m above the ground.To achieve this vertical leap, with what force did the impala push down on the ground?Express your answer to two significant figures and include the appropriate units.Fpush = What is the ratio of this force to the antelope's weight?Express your answer using two significant figures.Fpush / w =

###### FREE Expert Solution

Gravitational potential energy,

$\overline{)\begin{array}{rcl}{\mathbf{U}}& {\mathbf{=}}& \mathbf{m}\mathbf{g}\mathbf{h}\end{array}}$

Kinetic Energy,

$\overline{)\begin{array}{rcl}\mathbf{K}\mathbf{.}\mathbf{E}& {\mathbf{=}}& \frac{\mathbf{1}}{\mathbf{2}}{\mathbf{mv}}^{\mathbf{2}}\end{array}}$

Newton's second law,

$\overline{)\begin{array}{rcl}{\mathbf{\Sigma F}}& {\mathbf{=}}& {\mathbf{ma}}\end{array}}$

Acceleration and velocity,

$\overline{)\begin{array}{rcl}{\mathbf{a}}& {\mathbf{=}}& \frac{\mathbf{∆}\mathbf{v}}{\mathbf{∆}\mathbf{t}}\end{array}}$

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###### Problem Details

An impala is an African antelope capable of a remarkable vertical leap. In one recorded leap, a 45 kg impala went into a deep crouch, pushed straight up for 0.21 s, and reached a height of 2.5 m above the ground.

To achieve this vertical leap, with what force did the impala push down on the ground?

Express your answer to two significant figures and include the appropriate units.

Fpush

What is the ratio of this force to the antelope's weight?