Equivalent Circuit
(Ideal String Struck by a Mass)

• Mass = inductor of $m$ Henrys (impedance $ms$)
• String endpoint = resistor of $R$ Ohms (impedance $R$)
• One common velocity for all three elements $\Rightarrow$ series
• Series order is arbitrary
• Note that string wave impedance appears twice
• ``Polarity'' (reference direction) for each element defines ``positive'' current for that element:
  Current is positive when flowing from $+$ to $-$
• Positive current corresponds to a positive voltage drop