How Much Work is Done Raising a Load with a Two-Pulley System?

[mia_material_x1]

Homework Statement

A 60 kg load is raised by a two-pulley arrangement. How much work is done by the
force F to raise the load 3 m if there is a frictional force of 20 N in each pulley? Note that the pulleys do
not rotate, but the rope slides across each surface.

I've solved the problem, I would like to know if my answer is right. Otherwise, could you please tell me where I did wrong. thanks guys!

Homework Equations

F=mg
W=F*d

The Attempt at a Solution

m = 60kg
F(friction) = 20N
d = 3mF=mg∕2 + 2F(friction) = (60kg×9.8m/s²)/2 + 2×20N = 334N
W=F×2d= 334N ×2 × 3m = 2004 J

 

[stockzahn]

Seems to be correct.

 

[BvU]

And the question you want answered by PF is ?

Note that you can get an answer to "is this right?" by handing in your homework to Teacher !
And that it isn't PF culture to provide yes/no correct stamps, so you'll have to ask such things a bit more subtly...