- #1
amal
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Homework Statement
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The coefficient of static friction [itex]μ_s[/itex] between the 100kg block and wedge is [itex]0.20[/itex]. Determine the magnitude of force [itex]P[/itex] required to raise the block if the rollers are frictionless and wedge massless. You may take [itex]g=9.8m/s^2[/itex]
Homework Equations
[itex]f=μ_s*N[/itex]
The Attempt at a Solution
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The block will move whenever there is relative motion between block and wedge.
Now,
[itex]N_1+Psinθ=Wcosθ[/itex]
[itex]N_1=Wcosθ-Psinθ[/itex]
[itex]f=μ_sN_1[/itex]
For impending motion,
[itex]f=Psinθ[/itex]
That will give:
[itex]P={\frac{Wμcosθ}{cosθ+μsinθ}}[/itex]
Plugging in the values,
[itex]P=186.03N[/itex]
Only that my teacher thinks that the answer is wrong. According to him, P should be 465N and N1 should be 1073N odd. Though he didn't elaborate, he thinks that something is wrong with my resolution of P. I don't understand how and I also don't understand why the normal is greater than the weight of the block.
Please Help.