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3 years ago

10

While moving in, a new homeowner is pushing a box across the floor at a constant velocity. The coefficient of kinetic friction b

etween the box and the floor is 0.437. The pushing force is directed downward at an angle θ below the horizontal. When θ is greater than a certain value, it is not possible to move the box, no matter how large the pushing force is. Find that value of θ.

1 answer:

tresset_1 [31]3 years ago

6 0

Answer:

64.1°

Explanation:

Coefficient of friction = Horizontally resolved pushing force divided by Moving force

Coefficient of friction is 0.437

Resolving pushing force to horizontal = Moving force * Cos ∅

Therefore, 0.437 = Cos ∅

and ∅ = Arch Cos 0.437 = 64.1°

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Answer:

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Given that $R_1=R_2$ and $l_1=l_2$

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$\Rightarrow( \frac{d_1}{d_2} )=\sqrt{\frac{1.68\times 10^{-8}}{5.6\times 10^{-8}}}$

$\Rightarrow( \frac{d_1}{d_2} )=\sqrt{\frac{3}{10}}$

$\Rightarrow d_1:d_2=\sqrt{3} :\sqrt{10}$

Therefore the ratio of diameter of the copper to that of the tungsten is

$\sqrt{3} :\sqrt{10}$

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