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Old 11-22-2012
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Re: Riddles with a Prize, by Mantus Anchors

F = mass * acceleration (F= m*a), and weight = mass * gravity

In order for the box to "jump" off the surface it's sitting on (assuming earth with g=9.8m/s^2), the upward force, F(u), would need to be greater than the weight of the box which is (M+m)*9.8 m/s^2.

Whatever downward force, F(d), is applied to the Jack will be returned with the Jack is released. Therefore, the force applied to just overcome the weight of the Box+Jack would be F(d) > (M+m)*9.8 m/s^2

If this isn't the answer, then all I can say is F(u). ;-)

Last edited by Capt-T; 11-22-2012 at 01:30 AM. Reason: change = to >
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