Q1. On a workday the average decibel level of the busy street is 82 dB, with 100 cars passing a given point every minute. If the number of cars is reduced to 10 every minute on a weekend, what is the decibel level of the street?
Q2. One mole of magnesium (6 1023 atoms) has a mass of 24 grams, and its density is 1.74 grams per cubic centimeter. You have a long thin bar of magnesium, 2.5 m long, with a square cross section, 0.07 cm on a side.
Next you eliminate the 11 kg mass, place the rod horizontally, and strike one end with a hammer. How much time t would elapse before a microphone at the other end of the bar will detect a disturbance?