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Q & A: momentum and kinetic energy

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Most recent answer: 10/22/2007
Are momentum and kinetic energy the same thing?
- John Doe (age 99)
John- I've followed your work in many areas, especially the law, and am a big fan. It's nice to see that you're still taking an active interest in science at your advanced age.

Momentum and kinetic energy are entirely different things. Momentum is a VECTOR (points in some direction) with dimensions mass*length/time. Kinetic energy is a SCALAR (plain number) with dimensions mass*length^2/time^2.

There was some confusion a few hundred years ago about which of these was a better 'measure of motion'. We actually need both of them to get useful descriptions of most events.

Give our regards to Jane.

Mike W.

(published on 10/22/2007)

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