4. In question 3, will the measured wavelength of the sound be longer or shorter than if both you and the train were at rest?
a) longer because the pitch is higher
b) shorter because the pitch is unchanged
c) shorter because the pitch is higher
d) the same because only the pitch changes, not the wavelength

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.