Question

Police radar guns measure the speed of moving vehicles by transmitting electromagnetic waves at a vehicle and detecting a Doppler shift in the reflected wave. Suppose a police radar transmits at a frequency of 26.8 GHz and receives a wave reflected from a car moving toward the radar at 66.0 mph. Find the frequency shift

Answer 1

Frequency shift, f = 5270.66

Step-by-step explanation:

It is given that,

Velocity of the car, v = 66 mph = 29.50 m/s

Frequency transmitted by a police radar,
`F_s=26.8\ GHz=26.8* 10^9\ Hz`

Frequency shift is given by :

`f=(2vF_s)/(c)`

`f=(2* 29.50\ m/s* 26.8* 10^9\ Hz)/(3* 10^8\ m/s)`

f = 5270.66 Hz

So, the frequency shift is 5270.66 hertz. Hence, this is the required solution.