Sonometers, tuning forks, and wave periodicity

[Ahmed1029]

Summary: Cofnusion regarding waves on a sonometer band

A tuning fork is used to determine the wave frequency of a sonometer(according to my understanding), so whay about pulse waves? Does a pulse have a wave frequency? Couldn't a pulse travel over the sonometer band that can be determined by a tuning fork? Or are all waves that travel through a sonometer periodic? That makes me wonder when I can use the relation that says the velocity of a wave is equal to its wavelength multiplies by its frequency, is it also for periodic wavea only? I think it's obvious that I'm a bit confused, can someone hall clarify those things to me?

 

[sophiecentaur]

Summary: Cofnusion regarding waves on a sonometer band

so whay about pulse waves?

It depends on what experiment you have in mind. The basis of a sonometer is to resonate with a single driving frequency, afaik. I think you'd only be using fundamental or low overtones because a pulse consists of a range of frequencies and would disperse and the shape would be destroyed pretty quickly.
If you want to look at pulses on a string, I'd suggest you use a very long string and a sensor at different points along the string - different equipment needed.

 

[Ahmed1029]

It depends on what experiment you have in mind. The basis of a sonometer is to resonate with a single driving frequency, afaik. I think you'd only be using fundamental or low overtones because a pulse consists of a range of frequencies and would disperse and the shape would be destroyed pretty quickly.
If you want to look at pulses on a string, I'd suggest you use a very long string and a sensor at different points along the string - different equipment needed.

So if there is no dispersion, can I always assume the wave traveling through the sonometer band is periodic and has a well-defined wavelength and time period?

 

[sophiecentaur]

So if there is no dispersion, can I always assume the wave traveling through the sonometer band is periodic and has a well-defined wavelength and time period?

You can't rely on no dispersion. How do you propose to launch a pulse onto the wire? Post a diagram of what you hope to do.
If you are just trying to think outside the box then ask yourself how a pulse can be generated and detected. The sonometer is essential a resonant instrument with standing waves. This is not consistent with pulse transmission along a wire which requires a long wire with a transducer at one end, a long wire and a transducer at the other end which will absorb all the incident wave energy and suppress any reflection.

 

[Ahmed1029]

I'm just trying to solve this problem. Here m is the mass of the block, not the sonometer band. I'n supposed to get a number, but I keep getting an equation with 2 constants, one of which is linear mass density( which I want to find), while the other is wavelegnth. I made an assumption that the wave was periodic in soace and time, and that its frequency is the same as the frequency of the sound waves it produced. I'm not sure of any of those two assumption, and even when making them J still can't figure out the solution. Any insight?
Here is my attempt :

 

[TSny]

I think you can assume that the sonometer wire vibrates as a standing wave in the fundamental mode. Do you see how to determine the wavelength of the standing wave in terms of the distance $l$?