Can someone help me with this static friction problem?

AI Thread Summary
A 45-kg crate on a 24-degree inclined ramp begins to slide, prompting a calculation for the coefficient of static friction. The initial calculations included a weight of 441 N, with the normal force and static friction force incorrectly computed. It was noted that the user’s calculator was likely in radian mode, leading to incorrect values for mgcos24 and mgsin24. After receiving hints about the relationships between sine and cosine for angles less than 45 degrees, the user corrected their calculations. Ultimately, the user successfully found the correct answer with assistance from others in the discussion.
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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