Consider two different situations. in situation a, a box of mass m on a frictionless tabletop is being pulled by a constant horizontal force f = m g. in situation b, a box of mass m is on a frictionless tabletop and a string of negligible mass runs over a peg of negligible friction, to a hanging mass m which is allowed to fall.

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.