Discontinuity Waves: Deriving the expressions

In summary, the problem involves a long string with linear mass density μ_1 = 1.0 gr/cm and a long string with linear mass density μ_2 = 4.0 gr/cm joined together under constant tension. A transverse sinusoidal wave with amplitude A_i = 3.0 cm and wavelength λ = 25 cm is launched along the lighter string. The task is to derive the expressions for the incident, transmitted, and reflected waves, taking into account the equations y(x,t) = A sin(kx - ωt) and v = √(T/μ). This requires finding formulas for the waves on each string separately, and then determining the conditions where the two strings meet.
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Homework Statement




A long string of linear mass density [itex] μ_1 = 1.0 gr/cm [/itex] is joined to a long string of linear mass density [itex] μ_2 = 4.0 gr/cm [/itex] and the combination is held under constant tension. A transverse sinusoidal wave of amplitude [itex] A _i = 3.0 cm[/itex] and wavelength [itex] λ =25 cm [/itex] is launched along the lighter string.


Q. Derive the expressions for the incident, transmitted and reflected waves.


Homework Equations



[tex] y (x,t) = A \sin(k x -\omega t) [/tex]

[tex] v = \sqrt {\frac {T}{μ}} [/tex]

The Attempt at a Solution



Is there a way to derive the expressions mathematically? I know the reflected wave will have the same constant K as the incident wave but will be traveling to the left rather than the right and the transmitted wave will have a different k value than the incident wave but will be traveling to the left.

This is as far as I have gotten with the problem as I can write the expressions from them conclusions but not giving an expression for the amplitudes of the transmitted and reflected waves in terms of the incident wave or waves for the k constants.
 
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  • #2
You are clearly expected, in this problem, to be able to find formulas for a wave on a string with constant density. Do that for each string, separately, the determine the conditions where the two strings meet.
 

1. What are discontinuity waves?

Discontinuity waves, also known as shock waves, are abrupt changes in the physical properties of a medium, such as density, pressure, and temperature. They occur when a disturbance travels faster than the speed of sound in that medium.

2. How are the expressions for discontinuity waves derived?

The expressions for discontinuity waves are derived using the Rankine-Hugoniot equations, which are a set of conservation laws that describe the relationship between the properties of a fluid before and after a shock wave.

3. What factors affect the amplitude and speed of discontinuity waves?

The amplitude and speed of discontinuity waves are affected by the initial conditions of the fluid, such as its velocity and density, as well as the properties of the medium, such as its compressibility and viscosity.

4. Can discontinuity waves occur in all types of media?

Discontinuity waves can occur in any medium, as long as there is a sudden change in the physical properties of that medium. This includes gases, liquids, and solids.

5. What are the practical applications of studying discontinuity waves?

Studying discontinuity waves has many practical applications, such as understanding the behavior of supersonic aircraft and designing structures to withstand shock waves. It also has applications in fields such as astrophysics, where shock waves play a crucial role in the formation of stars and galaxies.

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