What Is the Coefficient of Kinetic Friction in Brenda's Wallpaper Project?

[sunfire249]

Homework Statement

Before hanging new William Morris wallpaper in her bedroom, Brenda sanded the walls lightly to smooth out some irregularities on the surface. The sanding block weighs 2.0N and Brenda pushes on it with a force of 3.0N at an angle of 30.0 degrees with respect to the vertical, and angled toward the wall. Draw a free body diagram for the sanding block as it moves straight up the wall at a constant speed. What is the coefficient of kinetic friction between the wall and the block?

Fn = 2.0N
Theta = 30.0
Fhand = 3.0N

Homework Equations

F = UkN
y-component = ycos(theta)

The Attempt at a Solution

I drew an FBD of a block on a vertical wall with Fn pointing in the downwards direction. I extended the top part of the block a little with a dotted line to show the continuation of the y-axis, and drew a line that represented the magnitude of the hand pushing at 30degrees.

My first attempt I tried 3.0cos(30.0) (because I reasoned that if you find the y-component to the force of the hand you would find the F needed for the equation F = UkN)
I got 2.6N from this, and reworked F = UkN so it would be Uk = F/N
I plugged in Uk = 2.6N/2.0N (Normal force of the block), and got 1.30 as an answer.

This answer seems a little large to me though, considering it's the coefficient of Static Friction. So I'm just wondering where I might have gone wrong?

 

[ehild]

The wall is vertical so the normal force is horizontal and not equal to the weight of the block, which points downward.

A good drawing always helps. Can you show yours?

ehild