A segment AA of wire stretched tightly between two posts a distance LL apart vibrates in its fundamental mode with frequency ff$.$ A segment BB of an identical wire is stretched with the same tension, but between two different posts. You observe that the frequency of the sacond harmonic of wire BB is the same as the fundamental frequency of wire AA$.$

Part A

The length of wire BB must be

LL$\mathrm{.}2$LL$\mathrm{.}4$LL$.$