In the rest position (at equilibrium) before the pendulum is swinging its KE = 0 and the GPE = 0. As the pendulum moves upwards it gains both KE and GPE and at its max height GPE = maximum, but there is a small moment when at the max height the pendulum does not move, so even though as the pendulum climbed upwards it gained KE, right at the top where it halts for just a split second, whilst GPE = max, KE = 0 (because there isn’t any movement). Now, as the pendulum comes back downwards from the max height, GPE starts to decrease and KE starts to increase. Once the pendulum is back at equilibrium, GPE is back to 0 but since the pendulum is always in motion if undampened, then the KE is max at the bottom. However, if the pendulum is made to stop at equilibrium, both GPE and KE are 0. The amount of energy exchanged between KE and GPE is the same as energy is conserved. KE + GPE = Mechanical energy (ME) ME in this system stays constant throughout. The proportions of KE and GPE change but always total the same and add up to the same ME as energy is conserved in a pendulum in constant motion.
Asked by Maahum
Can you please explain the motor effect, generator effect and dynamos in physics