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Ethan Godden
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1.Homework Statement
The wave function for a wave on a taunt string is:
y(x,t)=(0.350)(sin(10(π)(t)-3(pi)(x) +(π)/4)
where x and y are in meters and t is in seconds. If the linear mass density(μ) of the string is 75.0g/m, (a) what is tha average rate at which energy is transmitted along the string(P)? (b) What is the energy contained in each cycle of the wave?
General Wave Function: (A)(sin(kx-ωt))
P=(1/2)(μ)(ω2)(A2)(v)
Eλ=(1/2)(μ)(ω2)(A2)(λ)
k=(2π)/λ
ω=(2π)f
v=λf
My main question has to do with whether the angular wave number and/or the angular frequency can be negative. I am comparing the general wave function given in my textbook and the function given in the question, and the variables have different signs such as the "kx" be positive in the general function and negative in the question or the "ωt" being negative in the general function and positive in the question.
My first thought was that maybe the wave in this question is moving to the left as the general wave function changes to "(A)(sin(kx+ωt))" if this is the case, but when I did a bit of searching online, people said the wave is moving to the right. I am perplexed to how one can determine this.
I am pretty sure that whether k and ω are negative for this question does not matter because both would have the same sign as my solution below shows. I am just interested to know why k and ω are not negative and how one could determine the direction of motion for the wave from the quesiton.
Solution:
(a) k=(2π)/λ →λ=(2π/k) →λ=(2π)/(±3π)=±0.6666...rad/m
ω=(2π)f → ω/(2π)=f → ±(10π)/(2π)=±5Hz
v=λf → v=(±5)(±0.6666...)=3.33333...m/s
Input these values into the equation for P to get the average rate at which the energy is transmitted.
(b) Input the values into the equation for Eλ to find the energy contained in each cycle.
Also, if you wouldn't mind, please tell me if I am using this site correctly as this is my first post.
Thank You
The wave function for a wave on a taunt string is:
y(x,t)=(0.350)(sin(10(π)(t)-3(pi)(x) +(π)/4)
where x and y are in meters and t is in seconds. If the linear mass density(μ) of the string is 75.0g/m, (a) what is tha average rate at which energy is transmitted along the string(P)? (b) What is the energy contained in each cycle of the wave?
Homework Equations
General Wave Function: (A)(sin(kx-ωt))
P=(1/2)(μ)(ω2)(A2)(v)
Eλ=(1/2)(μ)(ω2)(A2)(λ)
k=(2π)/λ
ω=(2π)f
v=λf
The Attempt at a Solution
My main question has to do with whether the angular wave number and/or the angular frequency can be negative. I am comparing the general wave function given in my textbook and the function given in the question, and the variables have different signs such as the "kx" be positive in the general function and negative in the question or the "ωt" being negative in the general function and positive in the question.
My first thought was that maybe the wave in this question is moving to the left as the general wave function changes to "(A)(sin(kx+ωt))" if this is the case, but when I did a bit of searching online, people said the wave is moving to the right. I am perplexed to how one can determine this.
I am pretty sure that whether k and ω are negative for this question does not matter because both would have the same sign as my solution below shows. I am just interested to know why k and ω are not negative and how one could determine the direction of motion for the wave from the quesiton.
Solution:
(a) k=(2π)/λ →λ=(2π/k) →λ=(2π)/(±3π)=±0.6666...rad/m
ω=(2π)f → ω/(2π)=f → ±(10π)/(2π)=±5Hz
v=λf → v=(±5)(±0.6666...)=3.33333...m/s
Input these values into the equation for P to get the average rate at which the energy is transmitted.
(b) Input the values into the equation for Eλ to find the energy contained in each cycle.
Also, if you wouldn't mind, please tell me if I am using this site correctly as this is my first post.
Thank You