Physical Model
(Ideal String Struck by a Mass)

• String infinitely long -- no gravity or air
• Wave impedance $R$
• Mass $m$ strikes string at $x=0$ (a single point!)
• Collision speed $v_0$
• Horizontal motion neglected

At time 0, our model switches from

1. mass-in-flight and ideal string, to
2. two ideal strings joined by mass $m$ at $x=0$

Note that the mass and two string-segment impedances are in series because they all move together