Physics

Physics

Problem

Which expression represents the change in gravitational potential energy when a body of mass mm is moved vertically from height h1h_{1} to h2h_{2} near the Earth’s surface? a) 12mg(h22−h12)\frac{1}{2}mg(h_{2}^{2}-h_{1}^{2}) b) mg(h2−h1)mg(h_{2}-h_{1}) c) mg(h1−h2)mg(h_{1}-h_{2}) d) mgh2mgh_{2}
Intuitive explanation

Gravitational potential energy depends on height, so you need to find the difference between the final and initial states. The key insight is that near Earth's surface, gravitational potential energy is simply mghmgh at any height, so the change is just the difference of these two values. Pay attention to which height is final and which is initial—the sign tells you whether the body gained or lost potential energy.

Intuitive explanation

Gravitational potential energy depends on height, so you need to find the difference between the final and initial states. The key insight is that near Earth's surface, gravitational potential energy is simply mghmgh at any height, so the change is just the difference of these two values. Pay attention to which height is final and which is initial—the sign tells you whether the body gained or lost potential energy.

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