Gravitational Potential Energy

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Physics › Gravitational Potential Energy

Questions 1 - 3

1

A bouncy ball is dropped from . When it bounces back up is reaches a height of . How much energy was loss?

$g=10\frac{m}{s^2}$

Explanation

The formula for gravitational potential energy is:

To find the potential energy lost, we need to find the potential energy of the ball at two heights, then find the difference.

$GPE_{before} = 2kg (10\frac{m}{s^2})(10m)$

$GPE_{before} = 200J$

$GPE_{after} = 2kg (10\frac{m}{s^2})(8m)$

$GPE_{after} = 160J$

$GPE_{before} - GPE_{after} = GPE \ lost$

Note that the energy was not actually lost; rather, it was converted to kinetic energy.

2

A baseball weighing is dropped from a second story window which is high. What is the gravitational potential energy?

$g=10\frac{m}{s^2}$

Explanation

Gravitational potential energy is given by the equation:

We are given all the information needed to solve for the potential energy.

$g = 10\frac{m}{s^2}$

Plug in known values and solve.

$GPE= 2kg(10\frac{m}{s^2})(20m)$

$GPE = 400\frac{kg\cdot m^2}{s^2}$

Recall that the units for energy are Joules. Newtons is the unit for force.

3

A bowling ball is released from in the air. What is it's gravitation potential energy upon release?

$g=10\frac{m}{s^2}$

Explanation

The equation for gravitational potential energy is:

We are given all the information needed to answer the question.

$gravity=10\frac{m}{s^2}$

Plug in known values and solve.

$GPE = 15kg (10\frac{m}{s^2})(10m)$

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