Determining a specific frequency to make the ball bounce

AI Thread Summary
The discussion centers on the experiment of making a ball bounce using a stereo speaker connected to a function generator and a concave lens. It raises the question of whether the ball will bounce at a specific frequency and what causes this bouncing, suggesting that the vibration of the lens may be a key factor. Participants emphasize the importance of characterizing the force acting on the ball as a function of frequency and the timing of the ball's return to the lens to achieve constructive interference. Additionally, the relationship between frequency and the ball's acceleration is questioned, indicating a need for further exploration of these dynamics. Understanding these factors is crucial for successfully conducting the experiment.
chemaie
Messages
2
Reaction score
0
So, here's the set-up:

A small stereo speaker is connected to a function generator. A concave lens, bearing a ball is place over the speaker.

Now, the frequency is slowly increased in the function generator. My question is,
Will the ball really bounce at a certain frequency? Because I am not really sure about it. I just a found that set-up from a problem in a book and I want to try it for my research. And also, if it will bounce, what causes it to bounce? Is it the vibration of the lens?
 
Physics news on Phys.org
I have seen plenty of things bounce when affected by sound, so I think it must be true.
First, try to characterize the force acting on the ball. I would think that it must be the vibration of the lens, so force would be a function of frequency.
Next you would need to define the time it takes that ball to return to the lens. If the phase of the vibration is off, you will not get the constructive effects needed to keep the ball bouncing.
I would imagine you would need to consider both power and frequency, since the timing of the bounce would depend on both factors.
 
  • Like
Likes chemaie
Thank you for your response, RUber. I will try to consider the factors affecting the ball to bounce. Also, I would like to know the relationship of the frequency to the acceleration of the ball. Is there any relationship between the two?
 
I was using the Smith chart to determine the input impedance of a transmission line that has a reflection from the load. One can do this if one knows the characteristic impedance Zo, the degree of mismatch of the load ZL and the length of the transmission line in wavelengths. However, my question is: Consider the input impedance of a wave which appears back at the source after reflection from the load and has traveled for some fraction of a wavelength. The impedance of this wave as it...
Back
Top