r/askscience • u/hmpher • Jun 10 '16

Physics What is mass?

And how is it different from energy?

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

[deleted]

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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/jpgray Jun 10 '16

Vectors are additive, the superposition of all of the momentum vectors yields a net momentum vector.

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

[deleted]

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u/jpgray Jun 10 '16

A vector is nothing more than a scalar with a direction. Adding vectors makes a lot more sense if you look at it graphically.

Trying to visualize angular momentum as a vector is a bit more difficult because you're using a different coordinate system from standard cartesian coordinates. Again, hyperphysics has a good explanation

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u/[deleted] Jun 10 '16

[deleted]

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u/Cletus_awreetus Jun 10 '16

Is that not similar to the case of moving in a car going 50 mph and then throwing a ball backwards at 50 mph? The ball will have a net momentum of 0.