An important news announcement is transmitted by radio waves to people who are 130 km away, sitting next to their radios, and by sound waves to people sitting across the newsroom, 4.0 m from the newscaster. Who receives the news first? Take the speed of sound in air to be 343 m/s.

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.