Transverse Wave in a String Reflection and Transmission

AI Thread Summary
The discussion focuses on analyzing the reflection and transmission of a step pulse on a string with a spring at one end. The boundary conditions established include the continuity of deflection at the spring's location, represented by y(0-,t) = y(0+,t), which leads to the equation fi(-ct) + gr(ct) = ft(-ct). The participant is uncertain about the appropriate boundary condition to apply at the spring, considering the force balance, suggesting Ty' = ky at x = 0 as a potential condition. Further clarification on the correct application of these boundary conditions is sought to advance the problem-solving process. The conversation highlights the complexities involved in wave behavior at discontinuities in mechanical systems.
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A string with a density/length of rho and tension T has an elastic spring with stiffness k at x=0. There is a step pulse (fi = H(t)) incident on this discontinuity. Determine the reflected and transmitted waves.

Im not sure what boundary condition to use at the location of the spring. All I have now is:

BCs: (y(x,t) is deflection, fi(x-ct) is incident wave, gr(x+ct) is reflected, ft(x-ct) is transmitted)

y(0-,t) = y(0+,t) ----> fi(-ct) + gr(ct) = ft(-ct)

Not sure what other BC to use. Maybe Ty' = ky at x = 0? Where do I go from there?
 
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