when alternate masses are moving
in opposite directions, as shown in Figure 4.20(c). This gives an upper limit to
the highest normal frequency that is possible. If we simultaneously take the limits
N →∞,m→ 0 and l →0, in such a way that Nm remains finite, we indeed
obtain the situation of standing waves on a taut string. Thus we see that coupled
oscillators are the bridge between vibrations and waves. Our discussion of coupled
oscillators has also seen the repeated appearance of SHM again and again, and this
further emphasises the importance and diversity of this form of motion