Simple Pendulum

theta'' = -(g/L) sin(theta) - b*theta' -- the real nonlinear pendulum, not the small-angle approximation.

Length L (m) 1.50Gravity g (m/s^2) 9.81Damping b 0.10Initial angle theta0 (deg) 60

T_small = 2*pi*sqrt(L/g) = 2.46 s (small-angle approx)

theta = 60.0 deg

omega = 0.00 rad/s

at large theta0 the real period exceeds T_small