Stupid physics problem.

[Pat Fairbank]

I did the second problem and got the force of friction = 103.55 N, and mu = 0.67.

First, you find the weight of the box.
w=mg=(19)(9.8)=186.2 N

Then you find the parallel force and the normal force.
Fp=w*sin(angle)=186.2*sin(34)=104.12
Fn=w*cos(angle)=186.2*cos(34)=154.37

So by F=ma:
Fp - F(friction) = ma
104.12 - F(friction) = (19)(0.03)
F(friction)=103.55 N

Now we can solve for mu:
F(friction)=mu*Fn
103.55=mu*154.37
mu=0.67

Does this help at all?

[russell]

Constant velocity means no acceleration. Thus this means that there is no net force being acted upon it. That means that she must pull down with the same force that she weighs.

I have never taken physics, so feel free to ignore this but I would think that if she was pulling down with force equal to that with which gravity acts on her body then she would not go anywhere at all. She would stay exactly where she was. In order for there to be no acceleration (or constant velocity) all she would have to do is pull with constant force.