Sample Problems
A 2 kg car moving with a speed of 2 m/sec starts up a hill. How high does the car roll before
it stops?
KE in the beginning = PE at the end
E
k
=
E
p
½ mv
2
= mgh
½ (2) kg x (2 m/s)
2
= 2 kg x 10 m/s
2
x ???
4 Joules = 20 x ???
Height = 0.2 meters

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P a g e
Class Work
1.
Theresa’s 5.45 kg dog, Mr. Muggles is napping on top of 2 meter high couch.
What is the potential
energy of Mr. Muggles?
Looking For
Given
Relationship
Solution
Potential energy
m=5.45 kg
h=2m
g=10 m/s
2
PE=mgh
109 Joules
2.
Garfield (mass = 10.5 kg) is sleeping on top of the 3 meter high couch.
What is Garfield’s potential
energy?
Looking For
Given
Relationship
Solution
Potential energy
m=10.5 kg
h=3 m
g=10 m/s
2
PE=mgh
315 Joules
3.
A 200 kg pig is standing on top of a 40 meter high muddy hill.
What is the pig’s potential energy?
Looking For
Given
Relationship
Solution
Potential energy
m=200 kg
h=40 m
g=10 m/s
2
PE=mgh
80,000 Joules
4.
Tyler (mass=50-kg) is riding in a go-kart down maple avenue.
a.
What is Tyler’s kinetic energy if he travels at 2 m/s?
Looking For
Given
Relationship
Solution
Kinetic energy
m=50 kg
v= 2 m/s
KE=1/2 mv
2
100 Joules
b.
What is Tyler’s kinetic energy if he travels at 4 m/s?
Looking For
Given
Relationship
Solution
Kinetic energy
m=50 kg
v= 4 m/s
KE=1/2 mv
2
400 Joules