## Potential Energy Problems

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

4 kg means what?

- m (mass)
- h (height)
- v (velocity)
- F (force)
- a (acceleration)
- t (time)
- W (work)
- d (distance)

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

m = 4 kg

3 m means what?

- m (mass)
- h (height)
- v (velocity)
- F (force)
- a (acceleration)
- t (time)
- W (work)
- d (distance)

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

m = 4 kg

h = 3 m

What is g?

- Acceleration of gravity
- The force of gravity
- The mass factor of gravity
- The speed of gravity

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

m = 4 kg

h = 3 m

g = acceleration of gravity

g is how much?

- 9.8 m/s
^{2} - 15 m/s
^{2} - 3 m/s
^{2} - 12.2 m/s
^{2}

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

m = 4 kg

h = 3 m

g = 9.8 m/s^{2}

To make calculations easier, what can we use for g instead?

- 10 m/s
^{2} - 9 m/s
^{2} - 9.5 m/s
^{2} - 11 m/s
^{2}

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

m = 4 kg

h = 3 m

g = 10 m/s^{2}

What is the equation for Potential Energy?

- GPE = mgh
- F = ma
- KE = 1/2 mv
^{2} - S = D/t
- p = mv
- W = Fd
- V = IR

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

m = 4 kg

h = 3 m

g = 10 m/s^{2}

Equation: Ep = mgh

What does "mgh" mean?

- m x g x h
- m ÷ g ÷ h
- m + g + h
- m - g - h

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

m = 4 kg

h = 3 m

g = 10 m/s^{2}

Equation: Ep = mgh

Which of the following is right?

- Ep = 4kg x 10 m/s
^{2 } x 3 m - Ep = 4 kg x 10 m/s
^{2 } ÷ 3 m - Ep = 4 kg ÷ 10 m/s
^{2} ÷ 3 m - Ep = 4 kg + 10 m/s
^{2} + 3 m

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

m = 4 kg

h = 3 m

g = 10 m/s^{2}

Equation: Ep = mgh

Ep = 4kg x 10 m/s^{2 } x 3 m

So, Ep = ___ (no units, yet)

- 120
- 30
- 40
- 1200

*A 4 kg rock is sitting on a 3 m ledge. How much potential energy does it have?*

m = 4 kg

h = 3 m

g = 10 m/s^{2}

Equation: Ep = mgh

Ep = 4kg x 10 m/s^{2 } x 3 m

So, Ep = 120

What are the units for Ep?

- Ep = 120 J
- Ep = 120 w
- Ep = 120 kg
- Ep = 120 m