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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