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Q & A: Retarding Forces

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Most recent answer: 10/22/2007
Q:
Forces that resist motion are called what kind of foces?
- Tim (age 11 )
Cincinnati
A:
Tim -

I was actually just reading about this in my Physics book, so you're in luck. Forces that resist relative motion (like air resistance or friction) are called 'retarding forces'. Sometimes they are also just called 'resisting forces', though. Whether the forces actually 'resist motion' depends on who's looking at a particular situation. It's air friction that makes a leaf travel along in the wind. When you pick up a pencil it's friction with your fingers that gets the pencil in motion. In each case, the friction tends to make the two neighboring things (like the air and the leaf) move together. No force can in general 'resist motion' make things stop moving because it doesn't mean anything to say whether something is moving or not, only whether it's moving relative to something else.

-Tamara (and Mike)

(published on 10/22/2007)

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