1-A car traveling at 49 m/s and a truck traveling at 15 m/s are on the same straight road. The automobile horn has a frequency of 403 Hz. What is the change in frequency observed by the truck driver once the automobile has passed him? It is assumed that the automobile and the truck are traveling (a) in the same direction; (b) in opposite directions.

2-If a single person shouts in the stands of a stadium, the intensity in the center of the field is 52 dB. What is the loudness in decibels when 6.1104 spectators are shouting from roughly the same distance?