# Potential energy and average force? [closed]

A body of mass $15\,kg$ originally at rest $5\,m$ above the ground falls and penetrates $15\,cm$ into soft earth.

• Determine the loss of potential energy
• Determine the average resistance of the earth

Please help explain and solve this. I got 735 Joules as the potential energy $E_{pot}=m\cdot g\cdot h$.

As for the other one I am stumped.

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## closed as too localized by Mark Eichenlaub, Qmechanic♦Feb 28 '13 at 7:29

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

Too localized? On what grounds? Too Localized should be retired. – Mob Feb 28 '13 at 7:32
Generally we like questions that would be of interest to lots of people, and the answer to your homework is only likely to be of interest to you: hence the Too Localized flag. – John Rennie Feb 28 '13 at 8:00

The forum rules require we don't answer homework questions or confirm whether answers are correct, but consider this. The force on the falling object is $mg$, and if it falls a distance $h$ then the work done on it is force times distance or $mgh$, which is why you get the formula $mgh$ for the energy change. You can apply exactly the same reasoning to the slowing of the object after it touches the surface of the earth. – John Rennie Feb 28 '13 at 7:35