Summary and Main Ideas
Summary and Key Concepts
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The gravitational potential energy of an object is the energy the object has because of its position in the gravitational field relative to some reference point.
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The kinetic energy of an object is the energy the object has due to its motion.
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The mechanical energy of an object is the sum of the potential energy and kinetic energy of the object.
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The unit for energy is the joule (\(\text{J}\)).
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The Law of Conservation of Energy states that energy cannot be created or destroyed, but can only be changed from one form into another.
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The Law of Conservation of Mechanical Energy states that the total mechanical energy of an isolated system (i.e. no friction or air resistance) remains constant.
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The table below summarises the most important equations:
Table: Units used in Mechanical Energy
|
Potential Energy |
\({E}_{P}=mgh\) |
|
Kinetic Energy |
\({E}_{K}=\frac{1}{2}m{v}^{2}\) |
|
Mechanical Energy |
\({E}_{M}={E}_{K}+{E}_{P}\) |
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Physical Quantities |
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Quantity |
Unit name |
Unit symbol |
|
Potential energy (\({E}_{P}\)) |
joule |
J |
|
Kinetic energy (\({E}_{K}\)) |
joule |
J |
|
Mechanical energy (\({E}_{M}\)) |
joule |
J |
This lesson is part of:
Work, Energy and Power