Suppose that a police car on the highway is moving to the right at 20 m/s, while a speeder is coming up from almost directly behind at a speed of 31 m/s, both speeds being with respect to the ground. The police officer aims a radar gun at the speeder. Assume that the electromagnetic wave emitted by the radar gun has a frequency of 9.0 x 10^9 Hz.
(a) Find the magnitude of the difference between the frequency of the emitted wave and the wave that returns to the police car after reflecting from the speeder's car.
____________Hz
(b) Which wave has the greater frequency?
-The emitted wave has the greater frequency.
-The wave that returns to the police car has the greater frequency.
Why?
1 answer