Calculating Car Speed from Horn Frequency

AI Thread Summary
To calculate the speed of a car approaching with a horn frequency of 450 Hz, while the observed frequency is 503.7 Hz, the Doppler effect must be applied. The speed of sound is given as 1100 ft/sec. Relevant equations include those relating frequency, wavelength, and velocity of sound waves, as well as specific Doppler effect formulas. The discussion highlights the need for a clearer understanding of these equations to solve the problem effectively. The user seeks guidance on how to begin the calculations.
Moroni
Messages
11
Reaction score
0

Homework Statement



A car approaches blowing its horn. The observed frequency is 503.7 Hz Assume that the speed of sound is 1100 ft/sec. the car's horn has a frequency of 450 Hz How fast is the car traveling.




Homework Equations


?



The Attempt at a Solution



I can't even figure out how to start. Sorry for my ignorance.
 
Physics news on Phys.org
Thread moved from Advanced to Intro Physics.

Try again to list the relevant equations. What equation relates the frequency, wavelength and velocity of sould waves? What equations are you shown in your text or other learning materials for the Doppler effect? What does the wikipedia.org page say about the Doppler effect?
 
cb694f347a7ff458020624f46c56faf8.png


Is this it?

Thank You!
 

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 »
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 »

Similar threads

Travelling towards a Canyon Wall: Calculating Beat Frequency
Replies
3
Views
2K
Calculating frequencies with the Doppler Effect
Replies
1
Views
3K
JF -"Discover the Relationship Between Observed Frequencies: Car 1 and Car 2"
Replies
15
Views
4K
How Does the Doppler Effect Explain Frequency Changes in Moving Cars?
Replies
3
Views
8K
Graphs of Frequency for Car Moving in a Circle
Replies
24
Views
3K
Calculating Intensities of Out-of-Phase Sound Waves
Replies
1
Views
2K
How Fast Was the Car Moving in the Radar Speed Trap Experiment?
Replies
8
Views
3K
Stuck for 2hrs on this frequency question
Replies
3
Views
3K
Calculating Doppler Effect: Car Speed and Frequency Analysis
Replies
15
Views
10K
Help with question on motion: Avoiding a rear-end collision
Replies
6
Views
3K

Hot Threads

Recent Insights

Back
Top