when is the KE equal to the PE in case of a simple pendulum?

Dear student,

If the energy is just equal to the critical value,there will be two possibilities. If the pendulum starts out in motion, it will approach its vertical position ever more closely, without reaching it in any finite time. Or, the pendulum could start out perched exactly in the vertical position. It will remain there indefinitely. If the energy is zero, the pendulum just hangs straight down.

If E is less than the critical value, then the kinetic energy gets “used up” before the pendulum reaches its vertical position. It turns around and goes back again (libration). If E is more than the critical value, there is kinetic energy left over at the top, so the pendulum keeps going around (rotation).

Hope this helps.

Regards

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