My name is Alexander FufaeV and here I write about:
Conservation of Momentum
Conservation of momentum is one of the laws of conservation in physics and applies when no force acts on a particle:
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Force is zero
\boldsymbol{F} = 0
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The Newton's 2nd law states the following:
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\boldsymbol{F} = \frac{\text{d}\boldsymbol{p}}{ \text{d}t }
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With Eq. 1
the time derivative of the momentum disappears:
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Momentum time derivative is zero
0 ~=~ \frac{\text{d}\boldsymbol{p}}{ \text{d}t }
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If the pulse does not change over time, it is constant:
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Constant momentum
\boldsymbol{p} = \boldsymbol{p}_0 = \text{const.}
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