(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A man pulls a crate of mass 67.0 kg across a level floor. He pulls with a force of 172.0 N at an angle of 28.0° above the horizontal. When the crate is moving, the frictional force between the floor and the crate has a magnitude of 124.0 N.

If the crate starts from rest, how fast will it be moving after the man has pulled it a distance of 2.70 m?

2. Relevant equations

W = Fsin(angle)

W = KE

KE = 1/2 m v^2

3. The attempt at a solution

I started by finding the net force so that I could use the work equation:

Fx = 172 cos(28) - 124 = 27.87 N

Fy = 172 sin(28) (Fn and W cancel) = 80.75 N

Fnet = sqrt(Fx^2 + fy^2) = 85.42 N

Work Equation

85.42(2.70)cos(28) = 203.6 J

KE Equation

203.6 J = .5 (67 kg) v^2

v= 2.47 m/s

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Velocity of a mass being pulled across a level surface

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