$\"\"$

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A patrol car is parked $\"\"$ from a long warehouse.

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The number of revolutions per minutes is $\"\"$ .

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From the figure, $\"\"$ .

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$\"\"$ , where $\"\"$ is the angle.

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Derivative of $\"\"$ is the angular speed.

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Consider $\"\"$ .

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Derivative on each side with respect to $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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Consider $\"\"$ .

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Substitute $\"\"$ and $\"\"$ in $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ ; $\"\"$ .