Doppler Effect a flying bat emits squeaks at a frequency of 85 khz if a stationary observer picks up the frequency of the squeaks as 80 khz is the bat moving towards or away from the listener ? determine the speed at which the bat is flying.
a. Moving away.
b. Fo=(Vs-Vo)/(Vs+Vb) * Fb = 80.
(343-0)/(343+Vb) * 85 = 80,
343/(343+Vb) = 80/85 = 0.941
322.8+0.941Vb = 343, Vb = 21.4 m/s.
b.
To determine whether the bat is moving towards or away from the listener and to calculate the speed at which the bat is flying, we can use the Doppler Effect formula. The Doppler Effect describes the change in frequency of a wave (in this case, sound waves) due to the relative motion between the source of the wave (the bat) and the observer (listener).
The formula for the Doppler Effect is as follows:
f' = f * (v + v₀) / (v - v₀)
where:
- f' is the observed frequency
- f is the emitted frequency
- v is the speed of sound
- v₀ is the velocity of the observer relative to the medium (in this case, the air)
Given:
- Emitted frequency (f) = 85 kHz
- Observed frequency (f') = 80 kHz
To determine if the bat is moving towards or away from the listener, we compare the observed frequency (f') with the emitted frequency (f). If f' is lower than f, it means that the bat is moving away from the listener. Conversely, if f' is higher than f, it means that the bat is moving towards the listener.
In this case, the observed frequency (f') is lower than the emitted frequency (f). Therefore, we can conclude that the bat is moving away from the listener.
Now let's calculate the speed at which the bat is flying. We can rearrange the Doppler Effect formula to solve for the velocity (v) of the bat:
v = [(v₀ * f) / (f - f')] - v₀
where:
- v is the velocity of the bat
- f' is the observed frequency
- f is the emitted frequency
- v₀ is the velocity of the observer
Given:
- Emitted frequency (f) = 85 kHz
- Observed frequency (f') = 80 kHz
- v₀ is the velocity of the observer (which is not given)
Please provide the value of v₀ (velocity of the observer) to calculate the speed at which the bat is flying.