Explore BrainMass

Standing waves on stretched string and resonance.

Please do questions 1-5. Going through this lab, please see data table in second attachment, stringlab2.doc, when tried to solve for V th and the rest everything went wrong. V th never even was close to V average. This is throwing everything off. All data is assumed to be correct, but again V th is off. If cannot read here is data from top of page given.

Total length of string is 157.3 cm
mu theoretical = mass/L total = 0.000153 kg/m
mass of string is 2.4 grams
length of standing wave string is 1meter

See attached file for full problem description.


Solution Preview

Please see the attached file.

The very first thing is the mass per unit length. The string given to measure mass per unit length is having a length of 1 m. (it is in the procedure)

Hence mass per unit length will be 2.4 gm/m = 2.4*10-3 Kg/m.

If you have measured mass of 157.3 m long string even then the mass per unit length comes out
Kg/m, not 0.000153 Kg/m.
With this the velocity of wave comes out to be

Vth.1 = m/s
Vth.2 = m/s
And Vth.3 = m/s

Secondly the length of vibrating string. What do you mean by total length of the string? This length is 157.3 cm and here I think you have taken the length of the whole string from the speaker pin to hanging mass.

This length must be the length between two extreme nodes. You have taken this length as 157.3 cm for all frequencies that is a ...

Solution Summary

The question was to explain the experiment and to arrange the data for the result.

First the basic concepts for the standing waves and the overtones are explained and than the experiment is discussed withe the errors in the observation and the data. The questions were discussed.