Potential Energy
DO YOUR WORK ON A SEPARATE SHEET OF PAPER. SHOW YOUR WORK AND INCLUDE UNITS!
1. Define potential energy.
Energy due to position.
2. What is the formula for potential energy?
GPE = mgh
3. What unit is used for potential energy?
Joules – 1 N x m
4. Which has more potential energy:
a. A 25 kg mass or a 30 kg mass at the top of a hill.
30 kg mass
b. A car at the top of the hill or the bottom of the hill.
car at the top of the hill
c. A plane on the ground or a plane in the air.
plane in the air
d. A full plane or an empty plane (both are flying at the same height)
full plane
5. John has an object suspended in air. It has a mass of 50 kilograms and is 50 meters above the
ground. Calculate the object’s potential energy.
GPE = mgh
GPE = ? J
m = 50 kg
g = 9.8 m/s2
h = 50 m
GPE = 50 kg x 9.8 m/s2 x 50 m
GPE = 24,500 J
6. Ms. Westendorf drops an object from 10 meters. She knows it did 50 J of work. What is the mass of the
object?
GPE = mgh
GPE = 50 J
m = ? kg
g = 9.8 m/s2
h = 10 m
50 J = m x 9.8 m/s2 x 10 m
50 J = m x 98
m = 0.51 kg
7. Brian has an object suspended in air. It has a mass of 100kg and is 25 meters off the ground. What is the
object’s potential energy?
GPE = mgh
GPE = ? J
m = 100 kg
g = 9.8 m/s2
h = 25 m
GPE = 100 kg x 9.8 m/s2 x 25 m
GPE = 24,500 J
8. The mass of a rock is 1220 kg. It had 400 J of potential energy before it rolled down a hill. Calculate the
height of the hill.
GPE = mgh
GPE = 400 J
m = 1220 kg
g = 9.8 m/s2
h=?m
400 J = 1220 kg x 9.8 m/s2 x h
400 J = 11,956 x h
h = 0.033 m