Question

The police use radar guns and the Doppler effect to catch violators. A police car is driving from right to left at 50 km / h, another man's car is driven at a speed of 150 km / h away from the police car in the same direction. A police radar gun emits an electromagnetic wave whose frequency is 5.0 × 107 Hz that is reflected from the oncoming car.

What is the difference between the frequency of the wave emitted by the gun and the frequency received by the man's car?
What is the difference between the frequency of the wave emitted by the gun and the frequency that returns to the police car?

Answer 1

Vo = 50 km/h 50851 mis = 13.89 mis 130x5 mis Vs 130 km/h = 36.11 mis s frequence emitted toy gun recived s's s'= (v tvo) fs by man car 7 v-us =1330 + 13.89 336 - 36.11 = 5.85x107 H2 - ) X 5x10 f" frequencency returing to police caur S''= 330.+36-11 330-13.89 = 6.77X107H2 ( )* 5.858607 a ofa f' fs = (0.85 X10 07) Hz b) of f"_fs = 1.778107 H2