g=4 pi (l/t square)

Answer 1

Maybe you mean:

g = 4 pi^2 (L/T^2)

simple pendulum length L, all mass
m at end, small angle

m g L theta = m L^2 omega^2 theta

omega^2 = g/L
but omega = 2 pi f = 2 pi/T

4 pi^2/T^2 = g/L

g = 4 pi^2 L / T^2