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moy13

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## Homework Statement

A factory worker pushes a 28.4 kg crate a distance of 4.6 m along a level floor at constant velocity by pushing downward at an angle of 31 degrees below the horizontal. The coefficient of kinetic friction between the crate and floor is 0.25.

What magnitude of force (Fpush) must the worker apply to move the crate at constant velocity?

## Homework Equations

sum of Fx = Fpush*cos(31) - (kinetic friction) = 0

sum of Fy = n - Fpush*sin(31) - mg = 0

total work = K2 - K1 = 0

work = F dot s = Fscos(31)

kinetic friction = mu-sub-k * n

## The Attempt at a Solution

Fpush = (kinetic friction) / cos(31)

and

n = Fpush*sin(31) + mg

I need n, but I can't find it this way, what else can I do?

Thanks for any help.

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