How Is Work Calculated When a Block Is Pushed Up a Wall?

[Idividebyzero]

1. A 2.79 kg block is pushed 1.48 m up a vertical
wall with constant speed by a constant force
of magnitude F applied at an angle of 60.8
with the horizontal.
The acceleration of gravity is 9.8 m/s2 .If the coefficient of kinetic friction between
the block and wall is 0.581, find the work done
by F



2W=FD



3. seems pretty straight foward but i guess I am missing something. first attempt was W= (m)(g)(D)

W= (2.79kg)(9.8m/s^2)(cos(90-60.8))(1.48)
W=35.3J
that answer seems reasonable, but is not correct. first question is only asking what the work done by F is disregarding the friction. next question is about the work done by friction.(

 

[Doc Al]

first question is only asking what the work done by F is disregarding the friction.

I don't understand this comment. In any case, why not start by finding F? (Don't disregard friction!)

 

[Idividebyzero]

oh crud. i was getting this problem mixed up with another one no wonder the answer was wrong. it is asking for the net work

 

[Idividebyzero]

bump this is the last one giving me problems

 

[Doc Al]

it is asking for the net work

The net work done by all forces? No calculation needed for that.

Can you explain the calculation you did in the first post?