1. The problem statement, all variables and given/known data 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 133-lb door is at its geometric center. Neglect the small diameter of the wheels. 2. Relevant equations Fk=μkFN where FN is the normal force. 3. The attempt at a solution I thought symmetry of the door would result in 133/2 lb at each roller.