 Solution

ID: past-exam-of-the-physics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2011/paper-1/section-b/b7/ii/solution

d K = F_{net} \cdot d r

F = - \nabla U

and its work is

- Δ U

. Force is not generally a scalar derivative of total energy without specifying the displacement and the relevant energy.

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