That's at the highest point of the swing... whether it's in front or in the back ... at the instant when you stop going up and start coming down.
When you are swinging on a playground swing , your potential energy is greatest at the highest point
Your potential energy is greatest at the highest point of the swing, either at the front or back of the motion. This is when you have maximum height and, consequently, maximum gravitational potential energy. At this point, your kinetic energy is at its minimum.
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