WEBVTT

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Here is the problem: How much gravitational potential energy does a 75 kg mass gain when lifted 40 m (g equals 9.81 m/s squared)?

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Use the gravitational potential energy formula, rearranged for the unknown, in SI units.

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Formula: gravitational potential energy.

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Substitute the known values.

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So the answer is potential energy PE equals 29430 J.

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Gravitational potential energy is measured from a chosen zero level, so only changes in PE have physical meaning. Near Earth prime s surface deltaPE equals mgdeltah; a height below the zero level gives a negative PE.

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Substituted every value back into the formula: both sides agree, which checks out.