Simple Harmonic Equations

For springs	For pendulum	comments
$$F_{spring-restoring} = k \Delta{x}$$	$$F_{pendulum-restoring} = -m g\sin\theta$$
$$T_{period-of-oscillation} = 2\pi\sqrt\frac{m}{k}$$	$$T_{period-of-oscillation} = m g$$
$$k = m * \left(\frac{2\pi}{T}\right)^2$$
$$m = k * \left(\frac{T}{2\pi}\right)^2$$
$$x = A \cos (\omega t + \phi)$$		$$\omega \mbox{ is angular velocity in radians}$$ $$\phi \mbox{ initial angular displacement in radians}$$ $$\omega t \mbox{ displacement angle}$$
$$T = \frac{2 \pi}{\omega}$$
	$$\omega = \sqrt \frac{g}{l}$$
	$$T = 2 \pi \sqrt \frac{l}{g}$$