The equation of motion for a damped, sinusoidally driven pendulum in the earth's gravitational field is,

m L d^{2}q/dt^{2} + g dq/dt + m g sin q =
A sin( w t)

where q is the angle with respect to the vertical, m is the mass, L is the length, g is the acceleration of gravity and g is the damping. The driving force has amplitude A and driving frequency omega, w. Choosing units such that m, L, and g are all one, i.e., so called scaled units, simplifies the equation to:

d^{2}q/dt^{2} + g dq/dt+ sin q =
A sin( w t).

The Pendulum Physlet solves this differential equation using a 4th order Runge-Kutta algorithm.

`Note: Click inside the applet and press the spacebar to stop the animation. `

`Press the tab key to clear the phase and time graphs. This is useful to remove
transients.`

Visit the Physlets Page or contact Wolfgang Christian . |