Potential Energy
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Sample Problem: What is the
gravitational potential energy of a
girl who has a mass of 40 kg and is
standing on the edge of a diving
board that is 5 m above the water?
**Solve using the 4 steps**
GPE = mgh
Kinetic Energy
=
Sample Problem: What is the kinetic Sample Problem: A satellite falling to
energy of a girl who has a mass of
earth has a kinetic energy of 180.2
40 kg and a velocity of 3 m/s?
billion J and a potential energy of 1.2
billion J. What is its mechanical energy?
**Solve using the 4 steps**
**Solve using the 3 steps**
KE = ½ mv2
ME = PE + KE
KE = Kinetic Energy __________________
ME = Mechanical Energy ________________
GPE= Gravitational Potential Energy
___________________________________________ m= mass _____________ (in kg)
m = mass _____________ (in kg)
Mechanical Energy
v= velocity _________________(in m/s)
PE = Potential Energy ___________________
KE = Kinetic Energy ______________________
g = gravity 9.8 m/s2
h= height _________
(in meters)
GPE = mgh
GPE = 40 kg x 9.8 m/s2 x 5 m
GPE = 1960 kg m2/s2
GPE = 1960 J
KE = ½ mv2
KE = ½ x 40 kg x (3 m/s)2
KE = 180 N x m
KE = 180 J
ME = PE + KE
ME = 180.2 billion J + 1.2 billion J
ME = 181.4 billion J