Wave problem It's been driving my crazy for last hour

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Homework Help Overview

The discussion revolves around a wave problem involving both the propagation of a transverse wave in a string and the characteristics of two traveling waves that create a standing wave. The original poster presents equations related to wave motion and seeks to express the velocity of propagation and other parameters in terms of given variables.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to find the velocity of propagation by taking the partial derivative of the wave function. They express uncertainty about the definition of velocity of propagation and question their approach to part B, where they calculate parameters based on given values.

Discussion Status

Some participants are actively seeking assistance, indicating that they are struggling with the problem. The original poster expresses confusion about their calculations and the feedback received from the program. There is a lack of explicit consensus, but participants are engaging with the problem and exploring different aspects of the wave equations.

Contextual Notes

The original poster mentions specific values for amplitude, period, and speed, as well as the need to convert units. There is an indication that the homework platform is providing feedback on their answers, which may be influencing their approach.

asd1249jf
Wave problem! It's been driving my crazy for last hour!

Homework Statement


A)
Wave motion is characterized by two velocities: the velocity with which the wave moves in the medium (e.g., air or a string) and the velocity of the medium (the air or the string itself).

Consider a transverse wave traveling in a string. The mathematical form of the wave is y(x,t) = Acos2pi(kx-wt)

Find the velocity of propagation Vp of this wave.
Express the velocity of propagation in terms of some or all of the variables A, k, and W.

B)Two traveling waves move on a string that has a fixed end at . They are identical, except for opposite velocities. Each has an amplitude of 2.46 mm, a period of 3.65 ms, and a speed of 111 m/s.

The wave function of the resulting standing wave has the form y(x,t)=Asin(kx)sin(wt). Give the values of A, k, and W. Use meters (m) for A, inverse meters (1/m) for k, and inverse seconds (1/s) for W.




Homework Equations


A)
I believe I should use y(x,t) = Acos2pi(kx-wt)
B)
A is given
W=2(pi)f where f = 1/T
K = w/v

The Attempt at a Solution



A)
Ok so to find the velocity, we take the partial derivative and get
dy/dt = wAsin[kx-wt]

And I thought that was the answer but apparently it wasn't.

What is the velocity of propagation anyways? Maybe that's where I need to start.

B)
This one, I thought I had it right but apparently, Mastering Physics has been telling me its not.

Amplitude's given, so just convert 2.46mm to meters.

W(Omega) can be simply found by the equation w = 2pi/T

And since velocity is given, we can just plug that value in into k = w/v and find the wave number.

I got 2.46*10^-3 as Amplitude, 1720 for W and 15.5 for k and the program's telling me its wrong.

Am I tackling the problem wrong?

Any help would be deeply appriciated
 
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Can anyone help with this? I too have been trying to figure it out, only part B.
 


For the record, the answer turned out to be:

4.92×10−3, 15.5, 1720
 

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