Help Padford with Statics Homework: Friction Formula

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When dealing with stationary objects, the correct formula for friction is F ≤ μN, where μ represents the coefficient of static friction and N is the normal force. Static friction can vary up to this maximum value, which is why the inequality is used. The normal force changes with the angle of incline or decline, affecting the frictional force. Understanding the difference between static and kinetic friction is crucial, as the coefficients differ for each type. This clarification helps ensure accurate application of the friction formula in homework problems.
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now on question 8 of my homework, and i am starting to wonder if i;ve been getting these question right. It's to do with friction.

Relativally simple question: When an object is stationary, would the formula to find the resolved friction be: F = (mew, u) R or F (is less-than-or-equal-to) (mew, u) R?!
sorry bout the notation, have NO idea how to use it!
thanks in advance
Padford.
 
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friction

the normal force (force perpendicular to the plan of motion) is variable based on angle of incline or decline
 
thanks, but which formula applies to an object which is stationary, am i being stupid, co i swear our teacher told us one or the other?!
 
you have static and kinetic frction the difference is that the constants are different, think about sliding a large object its hard to get it sliding, but you get it sliding its not as hard,
 
Padford said:
Relativally simple question: When an object is stationary, would the formula to find the resolved friction be: F = (mew, u) R or F (is less-than-or-equal-to) (mew, u) R?!
Static friction is always less than or equal to \mu N, where N is the normal force pressing the surfaces together.
 
Thank you both very much! Very helpful :smile:

-Padford
 
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