How do radar guns work?

Answer 1

Some radars send out a signal in pulses which they listen for an echo.. with the echo it can be calibrated to tell your speed... something like this...

First pulse timed for echo tells how far away you are.. second pulse tells how far away you are for the second pulse and the difference of the distance between pulses tells how far you travelled and the time between pulses tells how much time.. so it can calculate your (change in distance)/(change in time) or your speed...

Some radars send out a signal and then tell how fast you are going by the doppler effect on the signal received back at the gun.. doppler effect.. like the high/low sound of a horn as a car passes you.. high as it approaches because soundwaves compressed.. low as it goes away because soundwaves spread out.

Answer 2

In a nutshell, it consists of a transmitter and a receiver. The "gun" sends out a wave at a very precise frequency, the wave strikes an object and is reflected back to the gun where the frequency of the reflective wave is compared to the original wave that was sent out.
When the object that reflects the wave is moving toward the wave, it "squeezes" the waveform together, raising the frequency of the wave. The difference between this frequency and the original frequency determines the speed of the object (usually my car.)
FYI: This is termed the "Doppler effect."

Answer 3

The gun sends out waves that hit the car and go back to the gun and the gun can interrupt how fast you are going because they measure the difference in how long it takes to get back to the gun every time it shoots out a different wave.

Answer 4

The same way as any other radar used to track airplanes.