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Blueman52
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Homework Statement
Suppose a thin rod of silver (E = 83 GPa, [itex]\rho[/itex] = 10.5 g/cm3) is joined to a thin rod of gold (E = 78 GPa, [itex]\rho[/itex] = 19.3 g/cm3).
Both rods have the same cross sectional area, and a longitudinal wave passes from the silver into the gold.
What amplitude will the transmitted and reflected waves be if the incident wave has amplitude 1?
Homework Equations
v = [itex]\sqrt{\frac{E}{\rho}}[/itex] (velocity)
Z = [itex]\frac{AE}{v}[/itex] (impedance)
The Attempt at a Solution
Esilver = 83 x 109 Pa.
[itex]\rho[/itex]silver = 1.05 x 104 Kgm-3.
Egold = 78 x 109 Pa.
[itex]\rho[/itex]gold = 1.93 x 104 Kgm-3.
= 2.812 x 103 ms-1.
= 2.010 x 103 ms-1.
= 2.952 x 107
= 3.881 x 107
Zsilver : Zgold
= 2.952 x 107 : 3.881 x 107
= 0.761 : 1
This is as far as I got.
I presume I have to multiply the amplitude with Zsilver : Zgold
= 1 x 0.761
= 0.761
but I don't know whether this is the amplitude of the reflected or transferred wave.
I would greatly appreciate any help at all.
Thank you!