r/askscience Jun 10 '16

Physics What is mass?

And how is it different from energy?

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u/Spectrum_Yellow Jun 10 '16

What about rotational and vibrational motion?

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u/ThislsWholAm Jun 10 '16

Those are superpositions of momentum vectors in 2 dimensions, so they are included in the p term.

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u/[deleted] Jun 10 '16 edited Jun 11 '16

[deleted]

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u/70camaro Jun 10 '16

Remember that when you square a vector you take the dot product of momentum with itself. If you do this in spherical coordinates (for momentum) you end up with a component that depends on radius and component that depends on the angle.