How to find the coefficient of friction?

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To find the coefficient of friction, the discussion revolves around applying Newton's second law, where the net force is the difference between the applied force and the friction force. Given a mass of 3.2 kg and an applied force of 22.8 N resulting in an acceleration of 3.02 m/s², the equations of motion are used to derive the coefficient. The key equations presented include ma = FA + FfK and ma = FA - Mmg, highlighting the relationship between forces. A correction is noted regarding algebraic manipulation, specifically the need to divide all terms by mg to accurately derive the coefficient. Understanding these equations and their proper application is crucial for calculating the coefficient of friction.
trASHf
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Homework Statement
Unknown object has a mass of 3.2kg on steel plank.

Add force:
|FA|=22.8N
|a|=3.02m/s^2

What is the material?
Relevant Equations
Newton's Second Law - sum of all forces = mass * acceleration = ...
GR (bold = mathematical convention)
m = 3.2kg
|applied force| = + 22.8 N
|acceleration| = + 3.02 m/s^2

FBD-hypothetical
^ normal force
|
friction force <-----*-----------> applied force
|
gravitational force

A
ma = FA + FfK
ma = FA -Mmg
ma/mg = FA - M
ma/mg - FA = -M
 
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Hi,

Can you imagine it is hard to make sense of this ? Read what you posted
 
Last edited by a moderator:
BvU said:
Hi,

Can you imagine it is hard to make sense of this ? Read what you posted

other than the attempted solution I put there, no I don't think it's hard to make sense of this.
 
trASHf said:
ma = FA + FfK
ma = FA -Mmg
ma/mg = FA - M
ma/mg - FA = -M
Your algebra is faulty when you go from the second equation to the third. You need to divide all the terms on the right side by mg.
 
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