Question

A police officer with an exceptionally good ear hears an approaching motorcycle. The engine sound he hears as the bike approaches is 195 Hz.

(a) Is the actual sound the bike makes higher or lower in pitch?

(b) What causes this frequency shift? Indicate with a diagram.

c) Then after the bike passes, he hears 147 Hz as the perceived pitch. If it was a nice sunny 20 °C day, how fast was the bike moving?

Answer 1