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Physics Questions

Started by Medeek, May 17, 2019, 01:27:14 PM

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Has anyone else ever wondered where the 1/2 comes from in the equation for the kinetic energy of an object (E=1/2mv^2)? It finally donned on me why, I probably could have realized why years ago but I never really thought about it until now.
Nathaniel P. Wilkerson, P.E.


The short answer is that it has to do with the integration of the momentum term in the derivation of the kinetic energy.

The more formal answer is:

Strangely enough I only thought about this while I was reading on a completely different topic and noticed that the equation given for the potential energy stored in a spring is E = 1/2kx^2. I occurred to me that this expression looked surprisingly similar to the expression for kinetic energy. It all became clear to me when I realized that the momentum is a linear function of the velocity (p=mv) as is the force a linear function of the displacement (F=kx).
Nathaniel P. Wilkerson, P.E.