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

A 800 N box was pushed up an incline plane of length 4.0m (measured along the incline) to a window ledge 2.0m above ground level. This process required that 3200J of work be done.

What was the average frictional force along the plane?

2. Relevant equations

W=Fd

3. The attempt at a solution

sin(theta) = 2/4

theta = 30 degrees

W = 800 N (4cos30)

W = 2771 J

W_friction = 3200 - 2771

= 429J

so the force done by friction would just be

429 = F(4cos30)

F = 124 N

This is wrong

the correct answer is 400 N

Thanks for any help :)

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# Homework Help: Box up a ramp - Work and friction force (easy)

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