The total energy of the system is conserved. Initially, the left pendulum is lifted to a given angle and released, and the right pendulum is vertical. At the onset of motion, the system energy is potential energy of the deformed spring and the raised left pendulum. Upon release, this potential energy steadily transforms into kinetic energies of pendulum motion. Note how the kinetic energy of the left pendulum gets completely transferred over to the right pendulum after a few cycles of swinging. At some instance in time, the right pendulum will swing as high as the initial position of the left, and the left pendulum will be vertical. The system motion will then repeat itself now only from right to left, and the initial starting position is reached again at a later instance in time. This interchange of potential and kinetic energy will continue indefinitely, causing the demonstrated motion.
To try this
simulation:
Press the 'Pause' button to stop the applet. While the applet is paused, you can adjust the spring strength as well as the pendulum length, weight and start position. You must press the 'Set' button in order for the changes to take effect. Press 'Play' for the applet to start again.
What's Going On?
This exhibit is a demonstration of Coupled Pendulums. As you swing back and forth you are mass, or bob, on the end of a pendulum. Your swing is attached to a pair of cables. These are connected to the other swing (or pendulum). The swinging motion of the pendulum on which you sit is coupled through the cable to the other pendulum. So, as you swing back and forth your motion (and energy) is transferred through the cable to the other pendulum.
