What are the equations for static and kinetic friction?

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The discussion focuses on the equations for static and kinetic friction, specifically addressing a box on a horizontal surface. The static friction equation is Fs = musFn, while the kinetic friction equation is fk = mukFn. To solve related problems, creating a free body diagram is recommended for clarity. It's emphasized that if the forces are unbalanced, the applied force (Fapp) does not equal the frictional force (Ff). Understanding these concepts is crucial for determining the coefficients of static and kinetic friction.
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Homework Statement



A box firstly at rest on a horizontel surface, needs a horizontal force to get it in motion. Though after in motion the box needs a force to keep in speed. Find static and kinetic coefficient of frictions.

Homework Equations



fk=mukFn
Fs=musFn

The Attempt at a Solution



I solved!
 
Last edited:
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Try drawing a free body diagram so you can see everything a little bit more clearly. After that, just try and figure out what you need to meet the specifications of your problem. If the forces are unbalanced, Fapp does not equal Ff.
 
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