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Gravitational Potential Energy
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Gravitational Potential Energy
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Gravitational Potential Energy
Potential energy exists whenever an
object which has mass has a position
within a force field. The most everyday
example of this is the position of objects
in the earth's gravitational field. The
potential energy of an object in this case
is given by the relation:
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PE = mgh
where
PE = Energy (in Joules)
m = mass (in kilograms)
g = gravitational acceleration of the earth (9.8
m/sec
2
)
h = height above earth's surface (in meters)
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Gravitational Potential Energy
Change in gravitational potential energy does not
depend on the path
A conservative force is one with this property: the work
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A conservative force is one with this property: the work
done by the force does not depend on the path.
conservative: gravity, electrostatic force, spring force…,
Nonconservative: friction, drag,
…
Work Done Lifting
Now, work is force times displacement. The force that you apply is equal to
the weight of the object. The weight of the object is its mass times the
acceleration due to gravity. And the displacement over which this work is
done is the height of the lift.
So, the work done lifting an object is equal to its mass times the acceleration
due to gravity times the height of the lift. This is summarized below:
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 Spring '10
 BalasubramaMaheswaran
 Physics, Conservation Of Energy, Energy, Potential Energy

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