Can someone help me with this static friction problem?

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Homework Help Overview

The problem involves a 45-kg crate on an inclined ramp that begins to slide at an angle of 24 degrees. The objective is to determine the coefficient of static friction between the crate and the ramp.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to analyze the forces acting on the crate using a free body diagram and applies relevant equations for static friction. Some participants question the accuracy of the calculations for the normal force and the frictional force components.

Discussion Status

Participants have provided feedback on the calculations, noting errors in the values derived from trigonometric functions. There is an acknowledgment of the correct application of formulas, but discrepancies in the numerical results are highlighted. The discussion reflects a collaborative effort to identify and correct misunderstandings in the calculations.

Contextual Notes

There is mention of potential issues with calculator settings, specifically whether it is in radian or degree mode, which may have affected the calculations. The original poster expresses confusion about the steps taken and seeks clarification on what might have been missed.

shaggyace
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Homework Statement



A 45-kg crate is placed on an inclined ramp. When the angle the ramp makes with the horizontal is increased to 24 degrees , the crate begins to slide downward. What is the coefficient of static friction between the crate and the ramp?


Homework Equations



\SigmaF=ma

fs=\musN


The Attempt at a Solution



I started by drawing a free body diagram. My weight came out to be -441 N. I have the angle of my weight at 24 degrees. The normal force at mgcos24, for which I got 187N. mgsin24 came out to be 399N which is also the static friction force. Then I just substituted into the static friction equation and my coefficient of static friction came out to be 2.13. I entered this into the homework problem which we do online and it is wrong. Did I miss a step? What did I do wrong?
 
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Your values for mgcos24 and mgsin24 are incorrect. Your calculator appears to be in radian mode.
 
The applied formula is right.The math is wrong.

the weight u calculated using m as 450 and g as 9.8 (all in SI units) is right as 441 N.

As u said normal force is mgcos24.
and mgsin24 as component of weight parallel to inclined plane.However, the calculated values are not right.

Hint(for angles less than 45 degrees cos x is always greater the sin x.

However, here your mgcos24 is less than mgsin24)
 
Last edited:
Wow, thanks a lot Calc class, lol.
Got the answer, thanks for your help guys
 

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