# Wave, finding the velocity of the incoming car.

• Physicsman567
In summary, the highway police use a radio wave with a frequency of 8 GHZ to measure the velocity of an incoming car. The reflected wave has a total frequency increased by 2100HZ. By using the equations V= F x ramda and V= S/T, as well as researching the Doppler effect, the speed of the incoming car can be calculated.

## Homework Statement

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The highway police, stationary hidden behind the barrier, shoot a radio wave that got a frequency of 8 GHZ, from his radar gun to measured the velocity of the incoming car, that's coming toward him. After the radio wave hit the car and reflect back, the police found that the total frequency is increase by 2100HZ. If the velocity of the radio wave in the air is 3x10^8 m/s, what's the speed of the incoming car?

## Homework Equations

3. The Attempt at a Solution
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I've tried to solve this question by combining the V= F x ramda, and V = S/T equation, but it doesn't give the correct answer. I'd also use the equation F=CF/2F, but again it doesn't thrive me the correct answer.

Hi Physicsman567, Welcome to Physics Forums.

For your problem you should research "Doppler effect" and "Doppler effect police radar" to find relevant equations.

Physicsman567
gneill said:
Hi Physicsman567, Welcome to Physics Forums.

For your problem you should research "Doppler effect" and "Doppler effect police radar" to find relevant equations.
I solved it!

## What is a wave?

A wave is a disturbance that transfers energy through a medium. It can be described by its wavelength, frequency, and amplitude.

## What is the velocity of a wave?

The velocity of a wave is the speed at which the wave travels through a medium. It is calculated by dividing the wavelength by the period of the wave.

## How do you find the velocity of an incoming car?

In order to find the velocity of an incoming car, you will need to measure the wavelength and frequency of the wave it produces as it approaches. Then, you can use the formula velocity = wavelength x frequency to calculate the car's velocity.

## What factors can affect the velocity of a wave?

The velocity of a wave can be affected by the properties of the medium it is traveling through, such as density and temperature. It can also be affected by external factors such as wind or obstacles in its path.

## Why is it important to calculate the velocity of an incoming car?

Calculating the velocity of an incoming car can help in various situations, such as traffic control, accident reconstruction, and determining the speed limit on a particular road. It can also provide valuable information for understanding the behavior of waves and their impact on the environment.