Solution
= Solution
For equal <linear mass densities> and common <tension>, $k_1=k_2$. The junction relations then give
$$
\boxed{r=0,\qquad t=1,\qquad\mathcal R=0,\qquad\mathcal T=1}.
$$
There is no mechanical-impedance discontinuity, so no reflected wave is needed to satisfy <displacement> and <force> continuity. The transmitted <displacement> is in <phase> with the incident wave and has the same <amplitude>; all incident <power> crosses the junction.