# PHYSICS-URGENT HELP

posted by .

A stationary police car emits a sound of frequency 1200 Hz that bounces off of a car on the highway and returns to the police car with a frequency of 1250 Hz. The police car is right next to the highway, so the moving car is traveling either directly towards or directly away from the parked officer. Determine the carâ€™s velocity, and whether the car was traveling towards or away from the police car.

• PHYSICS-URGENT HELP -

F = ((V + Vr) / (V + Vs)) * Fo = 1250.
((343 + Vr) / (343 + 0)) * 1200 = 1250,
Divide both sides by 1200:
(343 + Vr) / 343 = 1.0417,
Multiply both sides by 343:
343 + Vr = 357.29,
Vr = 357.29 - 343 = 14.3m/s Toward the
police car.

Vr = Velocity of the receiver(car).
Vs = Velocity of the source(police car.

• PHYSICS-URGENT HELP -

The answer said it was 7.02 m/s and not 14.3 m/s

## Similar Questions

1. ### Physics

Suppose that a police car on the highway is moving to the right at 20 m/s, while a speeder is coming up from almost directly behind at a speed of 31 m/s, both speeds being with respect to the ground. The police officer aims a radar …
2. ### Physics

Suppose that a police car on the highway is moving to the right at 20 m/s, while a speeder is coming up from almost directly behind at a speed of 31 m/s, both speeds being with respect to the ground. The police officer aims a radar …
3. ### physics

A speeding car is pulling away from a police car. The police car is moving at 30 m/s. The radar gun in the police car emits an electromagnetic wave with a frequency of 20.0 x 10^9 Hz. The wave reflects from the speeding car and returns …
4. ### physics

a car, moving at 100 mi/hr, passes a stationary police car whose siren has a frequency of 500 Hz. what is the frequency change heard by observer in the moving car as he passes the police car?
5. ### Physics help!

Suppose that a police car on the highway is moving to the right at 26 m/s, while a speeder is coming up from almost directly behind at a speed of 37 m/s, both speeds being with respect to the ground. The police officer aims a radar …

Suppose that a police car on the highway is moving to the right at 26 m/s, while a speeder is coming up from almost directly behind at a speed of 37 m/s, both speeds being with respect to the ground. The police officer aims a radar …
7. ### physics

Suppose that a police car on the highway is moving to the right at 26 m/s, while a speeder is coming up from almost directly behind at a speed of 37 m/s, both speeds being with respect to the ground. The police officer aims a radar …
8. ### physical

You are driving along a highway at 27.7 m/s when you hear a siren. You look in the rear-view mirror and see a police car approaching you from behind with a constant speed. The frequency of the siren that you hear is 1830. Hz. Right …
9. ### Physics

Suppose that a police car on the highway is moving to the right at 27 m/s, while a speeder is coming up from almost directly behind at a speed of 35 m/s, both speeds being with respect to the ground. The police officer aims a radar …
10. ### physics

A police car siren emits a sound wave with a frequency fs = 400 Hz and it is moving toward the wall at 25 /m/s. What frequency reflected from the wall does the driver of the police car hear ?

More Similar Questions