April 25, 2014
Calculating Energy - Chapter 15
Kinetic Energy Formula
KE = 1/2mv2
m = mass (kg)
v = velocity (m/s)
Energy Units: Joules (J)
April 25, 2014
A 0.10 kg bird is flying at a constant speed
of 8.0 m/s. What is the bird's kinetic
energy?
m = ____
v = ____
KE = 1/2mv2
April 25, 2014
Gravitational Potential Energy Formula
PE = mgh
m = mass (kg)
g = gravity (on Earth 9.8 m/s)
h = height (m)
April 25, 2014
A diver at the top of a 10.0 meter high diving
platform has a mass of 50.0 kg. Calculate
her potential energy relative to the ground.
m=
g=
h=
PE = mgh
April 25, 2014
1.) A lead weight having a mass of 30.0 kg is
dropped from a height of 40.0 m. What is the
PE of the weight right before it is dropped?
April 25, 2014
2.) A person is standing on top of the
terminal tower, 130.0 meters off the ground.
His PE is 70,000 J. What is the mass of this
person?
April 25, 2014
3.) A large rock with a mass of 50.0 kg and
2,000 J of energy rests at the top of a
mountain. How high off the ground is the
rock?
April 25, 2014
4.) How much KE does a baseball have if its
mass is 0.20 kg, and is moving at a velocity of
20.0 m/s?
April 25, 2014
5.) If a person is going 8.0 m/s and as a
mass of 90.0 kg, how much kinetic energy do
they have?
April 25, 2014
6.) What is the velocity of a 400.0 kg car
that has 360,000 J of KE?