Please check my solutions -- Mass being pulled with an angled rope

[ZurraMath]

A block of mass M = 4 kg is pulled by a force F = 100 N forming an angle of 60 degrees with themhorizontal plane with friction coefficient 0.3.

Determine the work of force F, friction force and normal force.

 

[berkeman]

Welcome to PF.

On your first solution, what are units of "S" for work? What units should Work be in?

 

[rsk]

I assume S to be the displacement?

 

[berkeman]

I assume S to be the displacement?

Oh, thanks. I guess the displacement is indeed a variable -- I missed that.

 

[Delta2]

The friction force is $$f=\mu N$$ and NOT $$f=\mu mg$$. So to correctly determine the friction force you need to find the normal force N first.
Your equation for the normal force N doesn't seem correct either (though the final result might be correct), it should be $$N-100\sin60=4\cdot 9.81$$ i.e. the force of 100N is actually forming an angle of -60 degrees with the horizontal, that is it is pointing down not up.