7) When damping occurs in a moving pendulum system, it may cause the:
A)Mass of the pendulum decrease
B)Length of the pendulum to increase
C)Period of the pendulum to decrease
D)Amplitude of the pendulum to decrease

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.