Answer:
the correct answer is 75 N
Explanation:
This is a translational balancing exercise, let's set a reference system with the x-axis in the direction of the plane and the y-axis perpendicular to the plane.
In this reference system the force to decompose is the weight
sin 42 = Wₓ / W
cos 42 = W_y / W
Wₓ = W sin 42
W_y = W cos 42
Wₓ = 112.1 sin 42 = 75.0 N
W_y = 112.1 cos 42 = 83.3 N
The expression for equilibrium on the x-axis is
Wₓ - fr = 0
fr = Wₓ
fr = 75.0 N
the correct answer is 75 N
