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- Homework Statement
- Suppose there are two strings with equal tension but different impedances attached to a ring on a vertical rod. If we shake the first string, it will make the ring slide and transmit the wave to the other string. As the ring slides on the rod, there is friction acting on it which is equal to F=b*v where b is coefficient of friction and v the speed of the ring. What is the value of b if there is no wave reflection?

- Relevant Equations
- F=Z*V

R=(Z1-Z2)/(Z1+Z2)

If we consider the coefficient b as the rings impedance, we can consider the effective impedance on the right to be b+Z2 where Z2 is the impedance of the second string. Then because there is no reflection it follows that Z1=b+Z2 or b=Z1-Z2.

Is this a valid solution? My professor went through a more complicated derivation which we concluded was wrong so I tried this. Is it correct? Can we suppose that the ring and string are connected in series and can we equate b with impedance? They match dimensionally so i don't see why not. Any help appreciated :)

Is this a valid solution? My professor went through a more complicated derivation which we concluded was wrong so I tried this. Is it correct? Can we suppose that the ring and string are connected in series and can we equate b with impedance? They match dimensionally so i don't see why not. Any help appreciated :)