In: Physics
The police use radar guns and the Doppler effect to catch violators. A police car is driving from right to left at 60 km/h, another man's car is approaching the police car, from left to right, at a speed of 130 km/h. A police-powered radar gun emits an electromagnetic wave whose frequency is 8 x 10^9 Hz that is reflected from the oncoming car.
a) What is the difference between the frequency of the wave emitted by the gun and the frequency received by the man's car?
b) What is the difference between the frequency of the wave emitted by the gun and the frequency that returns to the police car?