Chapter 4 - Graphs of the Circular Functions - Section 4.5 Harmonic Motion - 4.5 Exercises - Page 185: 14

$L=0.81$ ft

To find the length of the pendulum, we need to substitute the value of period $P=1$ sec in the formula and solve: $P=2\pi\sqrt {\frac{L}{32}}$ $1=2\pi\sqrt {\frac{L}{32}}$ $\frac{1}{2\pi}=\sqrt {\frac{L}{32}}$ $\frac{1}{4\pi^{2}}= {\frac{L}{32}}$ $\frac{32}{4\pi^{2}}= L$ $L=0.81$ ft