Calculating Well Depth: Solving for Standing Sound Waves at 48, 80, and 112 Hz

AI Thread Summary
To calculate the depth of the well based on the standing sound waves at frequencies of 48, 80, and 112 Hz, it's essential to recognize that these frequencies correspond to consecutive harmonics in a closed tube. The speed of sound is given as 343 m/s, which can be used to determine the wavelengths associated with each frequency using the formula wavelength = speed of sound / frequency. The depth of the well can then be calculated by relating the wavelengths to the harmonics, considering that the fundamental frequency and its harmonics will dictate the well's depth. It is crucial to analyze the relationship between the frequencies and the harmonics to find the correct depth. Understanding these principles will guide the solution to the problem effectively.
Angie913
Messages
17
Reaction score
0
There's this problem I'm having lots of trouble with. It is:
A person hums into the top of a well and finds that the standing waves are established at frequencies of 48, 80, and 112 Hz. The freq. of 48 Hz is not necessarily the fundamental freq. The speed of sound is 343m/s. How deep is the well?
I'm not sure where to start! The only equations we have for height are:
h=.5gt^2
and
h=velocitysound(t2-t1) which doesn't help! I'm not sure what I should use. Any hints are great! Thanks
 
Physics news on Phys.org
Okay, if you're lost when considering height, then try looking at the other parts of the problem.
 
Consider the relationship between wavelength and length of a one side closed tube. You may have to assume that the given frequencies corresponds to three consecutive harmonics (n, n+1 and n+2)
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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...
Back
Top