posted by Liz .
A ramp, a pulley, and two boxes.
Box A, of mass 10.0 kg, rests on a surface inclined at 37° to the horizontal. It is connected by a lightweight cord, which passes over a massless and frictionless pulley, to a second box B, which hangs freely as shown. If the coefficient of static friction is 0.40, determine what range of values for mass B will keep the system at rest.