The security alarm on a parked car goes off and produces a frequency of 1370 Hz. The speed of sound is 343 m/s. As you drive toward this parked car, pass it, and drive away, you observe the frequency to change by 147 Hz. At what speed are you driving?
use the doppler formula, moving observer.
I am not certain what is meant by the As you drive away...
I suspect the total doppler change 147hz from high to low, meaning the max dopper change was half that on approaching, and half when going away.
The security alarm on a parked car goes off and produces a frequency of 1010 Hz. The
speed of sound is 343 m/s. As you drive toward this parked car, pass it, and drive away,
you observe the frequency to change by 83 Hz. At what speed are you driving?
To determine the speed at which you are driving, we can use the Doppler effect formula:
Δf/f₀ = v/vo,
where:
Δf is the change in frequency,
f₀ is the original frequency,
v is the speed of the observer (you, the driver), and
vo is the speed of the source (the parked car).
In this case, we are given:
Δf = 147 Hz,
f₀ = 1370 Hz,
v = ?
vo = 0 m/s (since the car is parked).
By rearranging the formula, we get:
v = (Δf/f₀) * vo.
Substituting the given values, we have:
v = (147 Hz / 1370 Hz) * 0 m/s.
Calculating this expression, we find:
v ≈ 0 m/s.
Since the calculated speed is zero, it implies that you are driving at the same speed as the parked car.