Sanding block weighs 2.0 N and is pushed with a force of 3.0 N at an angle of 30.0 degrees with respect to the vertical, and angled toward the wall. Moves straight up the wall at a constant speed. What is the coefficient of kinetic friction between the wall and the block?

Answer 1

With an applied vertical force component of 3 cos 30 = 2.598 N, and a weight of 2.0 N, the friction force (downward on the block) must be 0.598 N

The force byt the block applied normal to the wall is 3.0 sin 30 = 1.50 N

The coefficient of kinetic friction of the sandpaper block is
0.598/1.50 = 0.40