A lot of problems I see have vertical mass-spring systems, where a mass m hangs from a spring with spring constant k stretching it a distance D, and usually all but one of those quantities is known. But would you equate the forces or the energies, i.e. which is the correct equation to use: mg=kD or mgD = 1/2kD^2, because the two give different answers.(adsbygoogle = window.adsbygoogle || []).push({});

Which is correct? Why is the other incorrect?

Thank You

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# Vertical mass-spring system - force or energy?

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