From this chapter on, I will use N for normal force and n for newtons. Recall the technique of rotating the coordinate axis. The only difference is the sign change. Notice that friction still opposes motion regardless of direction. Let T be the tension in the rope angled 30 degrees above the horizontal.
Constant speed implies no acceleration, thus no net force.
There will be two points of contact between the box and trough. The actual weight is 667 n. By the Third Law, this is equal in magnitude to the force exerted on him by the wheel. The radius is 15 feet and a point on the rim revolves once every 30 seconds. Use the circumference to find the velocity.