Coupled pendulum - Recording and evaluating with CASSY

Two coupled pendulums swing in experiment P1.5.4.4 in phase with a frequency f₁ when they are deflected from the rest position by the same distance. When the second pendulum is deflected in the opposite direction, the two pendulums oscillate in opposing phase with the frequency f₂. Deflecting only one pendulum generates a coupled oscillation with the frequency

in which oscillation energy is transferred back and forth between the two pendulums. The first pendulum comes to rest after a certain time, while the second pendulum simultaneously reaches its greatest amplitude. The time from one standstill of a pendulum to the next is called T_s. For the corresponding beat frequency, we can say