Question

How does the Doppler effect aid police in detecting speeding motorists?
@Abhisar

Answer 1

Hello @beccamarx19 !

Answer 2

Doppler radar sends a wave of frequency f\(_0\) to the moving car. The wave is reflected by the moving car, and since the source of the reflected wave is moving with respect to the observer, the frequency will change (Doppler Effect). If the car is moving toward the observer, the returned frequency is higher that that sent out. It is possible to calculate the speed of the car by comparing the original and returned frequencies.