Solving Coefficient of Friction Error on Webassign

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Homework Help Overview

The discussion revolves around calculating the coefficient of friction for a box sliding down an inclined plane, specifically focusing on the values used for the force of friction and the normal force. The problem is set in the context of physics homework on an online platform.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to calculate the coefficient of friction using the force of friction and normal force values but questions the accuracy of their normal force calculation. Some participants suggest that the normal force may have been incorrectly derived, while others point out potential issues with the value of gravitational acceleration used.

Discussion Status

Participants are actively engaging with the original poster's calculations, offering insights about possible errors in the normal force determination and suggesting a revision of the gravitational constant. There is a collaborative effort to identify the source of the discrepancy without reaching a definitive conclusion.

Contextual Notes

The problem involves specific values and conditions, such as the mass of the box, the angle of the incline, and the acceleration, which may influence the calculations. The original poster is also navigating the constraints of an online homework platform that may have its own requirements or limitations.

polarized
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Hello,

I'm in the middle of a problem on the online program Webassign, trying to calculate the coefficient of friction in a problem. I have the correct value of the force of friction, and I believe I have the correct Normal Force value, but the program is rejecting my answer.

The problem involved a 21kg box sliding down a 38 degree inclined plane at an acceleration .270 m/s^2, and I calculated the force of friction to be 121.033N. To solve for the coefficient of friction I am using the equation Ff=uFn → u=Ff/Fn= 121.033N/205.8N=.588

Did I make an error or is it a glitch in the program?
 
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Your normal force is incorrect, it seems.
If you used N=mg, that's where your mistake lies.
 
ooh yikes, thank you, I didn't notice that. And I drew the vector diagram too, so I should've realized lol. Thank you!
 
Use g as 9.81m/s^2 and not 9.8m/s^2 and you might get the right answer
 

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