Solve Whistle Frequency Homework: 11 Beats/s, 769 Hz, Answer in m/s

  • Thread starter Thread starter 05holtel
  • Start date Start date
  • Tags Tags
    Frequency
AI Thread Summary
To solve the problem, the frequency of the whistle is 769 Hz, and the beat frequency is 11 beats/s, leading to a perceived frequency of 780 Hz. The Doppler Effect is applied to determine the speed of the person moving towards the wall. The calculation involves using the formula for the Doppler shift to find the speed in m/s. The final answer should be presented as a numerical value with two significant figures.
05holtel
Messages
52
Reaction score
0

Homework Statement



You blow a whistle of frequency 769 Hz, as you move towards a wall.

The frequency of beats you hear from the whistle and the reflected sound is 11 beats/s.

How fast are you moving towards the wall?

Give your answer in m/s and to two significant figures.

Only answer in numerical values, no units.



Homework Equations





The Attempt at a Solution




769 + 11 = 780hz. Which I believe is the new frequency

Now what?
Thanks in advance
 
Physics news on Phys.org
You should use the Doppler Effect.
 
Thanks I got it
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

Doppler effect and beat frequency
Replies
3
Views
2K
Doppler Effect: Train A and B Whistle Frequency Calculation
Replies
1
Views
2K
Hearing the Train Whistle Frequency: Calculating fs
Replies
6
Views
5K
Travelling towards a Canyon Wall: Calculating Beat Frequency
Replies
3
Views
2K
Device that detect waves in a frequency range and beats
Replies
1
Views
2K
Finding frequency of moving sources with beats
Replies
2
Views
3K
How do I find the speed of this train?
Replies
1
Views
2K
What is the beat frequency for a cyclist ringing a bell towards a wall?
Replies
2
Views
2K
Beat frequency and velocity of observer
Replies
13
Views
4K
Doppler Effect: Velocity of a train
Replies
4
Views
2K

Hot Threads

Recent Insights

Back
Top