1. Determine the range of weights W for which the 100-lb block is in equilibrium. All wheels and pulleys have negligible friction.
2. The sliding glass door rolls on the two small lower wheels A and B. Under normal conditions the upper wheels do not touch their horizontal guide.
(a) Compute the force P required to slide the door at a steady speed if wheel A becomes "frozen" and does not turn in its bearing.
(b) Rework the problem if wheel B becomes frozen instead of wheel A. The coefficient of kinetic friction between a frozen wheel and the supporting surface is 0.30, and the center of mass of the 140-lb door is at its geometric center. Neglect the small diameter of the wheels.
ms = 0.30
mk = 0.25