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Q & A: What happens when push equals static friction?

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Most recent answer: 11/07/2014
Q:
If an applied force that exactly equals the max static friction is on an object, does the object start moving?
- Lee (age 13)
Houston
A:

That's a very interesting question. In the standard school description, the net force would still be zero so the object wouldn't slide. Yet if it did start to slide, the friction would drop to its  lower sliding value, and the object would accelerate. So the resting state isn't quite stable.

So I'd add to that description that there are always some thermal jiggles around. A tiny thermal jiggle might get the sliding started. So I guess that's what would happen. 

Mike W.


(published on 11/07/2014)

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