17 lines
855 B
Markdown
17 lines
855 B
Markdown
[[Work Energy and Power]]
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Formula is: $$K=\frac{1}{2}mv^2$$
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$K$ in joules
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$m$ in kg
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$v$ in m/s
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* Kinetic energy is scalar, only magnitude and never negative.
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* Because velocity is squared, changing speed affects energy more than changing mass.
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* For a system of objects, total kinetic energy is the sum of each object's kinetic energy.
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* Different observers in different reference frames can calculate different kinetic energies.
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If a dude standing on earth sees a 1kg ball travelling at 10m/s, he'll calculate it as 50J. If a dude taped to the ball calculates it he'll calculate 0J. If a theoretical god looked at it from a universal standpoint he'd probably calculate like $1*10^6$ Joules due to Earth orbiting the sun and the solar system orbiting the Milky Way.
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In a collision, total energy before and after is consistent in the observers frame.
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