Why is the mechanical advantage of using a single pulley always 1? assume there’s no friction. a. the input force is in a different direction than the output force. b. the input force is less than the output force. c. the input force is greater than the output force. d. the input force is equal to the output force.

The space between two 15-in.-long concentric cylinders is filled with glycerin (viscosity = 8.5 × 10-3 lb·s/ft2). the inner cylinder has a radius of 1 in. and the gap width between cylinders is 0.1 in. determine (a) the torque and (b) the power required to rotate the inner cylinder at 180 rev/min. the outer cylinder is fixed. assume the velocity distribution in the gap to be linear.