Asked by Shawna

A string along which waves can travel is 2.5 m long and has a mass of 300 g. The tension in the string is 72 N. What must be the frequency of traveling waves of amplitude 6.6 mm for the average power to be 68 W?
Answered by bobpursley
You know tension, mass/length, amplitude, power.
http://hyperphysics.phy-astr.gsu.edu/Hbase/Waves/powstr.html
The issue is what is wave velocity?

I see no indication that wave velocity can be determined from what is given. It would be helpful if wavelength were known, (f*Lambda=v), or v.

Answered by Shawna
What about v=sqrt(tension/(mass/Length))?
Answered by bobpursley
you can use that.
Answered by Shawna
I tried to use this...can you tell me if this is the wrong approach or please tell me what I am doing wrong as I keep arriving at the wrong answer.

I tried finding v=sqrt(t/u) where t is torque & u is density. I substituted u with mass/Length.

I used this value and sub'd into equation P=(1/2)uvw^2y^2 again subbing u with m/L. I got w=208.24

I used this answer to fond f=w/2pi
Answered by bobpursley
w^2= 2P/A^2 * sqrt (1/Tu)

I get not your answer. A= .06, u=.3/2.5, T= 250
Answered by Shawna
Thank you, you are always a great help!
Answered by bobpursley
A is .006m, not .06, typo.
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