When an ambulance is stationary, the siren gives off a sound at a frequency of 500Hz. In answering the following questions assume that the speed of sound is 340 m/s.

a.) What is the frequency of the stationary siren as perceived by an observer in a car driving toward the ambulance at 25 m/s?

b.)What is the frequency of the stationary siren as perceived by an observer in a car driving past the ambulance at a speed of 25 m/s?

c.) Would the answers found in parts a. and b. above turn out to be the same if the observer was stationary and the ambulance was traveling toward and past the observer at 25 m/s? Clearly and briefly explain why or why not.