Question

What energy changes are taking place in an oscillating pendulum?

Answer 1

As the pendulum swings down from an extreme position towards its mean position, its gravitational potential energy changes into kinetic energy. At the mean position, its kinetic energy is maximum and its potential energy is minimum. As it swings upwards, kinetic energy changes back into potential energy. At each extreme position, the pendulum momentarily comes to rest, so its kinetic energy is zero and its potential energy is maximum. Ideally, the total mechanical energy remains constant.