Question

A 23 kg box is being pulled by a rope at an angle of 30° above the horizontal. The applied force is 280 N. The coefficient of friction between the box and the surface is 0.42. Create a free-body diagram of this situation. Resolve all forces into their horizontal and vertical components for your FBD.

Answer 1

$mg_x=0,\\ mg_y=23·9.8=225.4\text{ N}.\\ F_x=280\cos30°=242\text{ N},\\ F_y=280\sin30°=140\text{ N}.\\ N_x=0,\\ N_y=mg_y-F_y=85.4\text{ N}.\\ f_y=0,\\ f_y=\mu N_y=0.42·85.4=35.9\text{ N}.$