The maximum potential energy of the child on the swing occurs when the child is at the highest point of the swing's arc. At this point, the child has the most potential to convert the potential energy into kinetic energy as she swings downwards. The maximum kinetic energy occurs when the child is at the lowest point of the swing's arc. At this point, the child is moving at her fastest speed, thus having the highest amount of kinetic energy.

This exchange of potential energy to kinetic energy is due to the conservation of energy principle. As the child swings upward, she gains potential energy since she is being lifted against the force of gravity. This potential energy is then converted back into kinetic energy as she swings downward, accelerating due to gravity's pull.

At the highest point of the swing, when the child momentarily stops moving upwards before descending, all her potential energy is stored. This potential energy is then gradually converted into kinetic energy as she starts swinging downward.

As the swing reaches its lowest point, the child's potential energy is at its minimum since she is closest to the ground. At this point, almost all the potential energy has been transformed into kinetic energy, resulting in the highest kinetic energy of the swinging system.

After reaching the lowest point, the kinetic energy begins to decrease as the child swings upward again, converting it back into potential energy. This energy conversion continues as the child swings back and forth, with the total energy (potential + kinetic) remaining constant.

To understand why the maximum potential energy of the child on the swing occurs at the highest point of the swing's arc, and why the maximum kinetic energy occurs at the lowest point, let's break it down:

1. Potential Energy: Potential energy is the energy an object possesses due to its position or configuration. In this case, the child on the swing has potential energy due to her height above the ground. The higher she is, the more potential energy she has.

Imagine the swing at its highest point. At this moment, the child is at her maximum height from the ground. Since potential energy depends on height, this implies that the child has the maximum potential energy at this point.

2. Kinetic Energy: Kinetic energy is the energy an object possesses due to its motion. In this case, the child on the swing has kinetic energy due to her swinging motion. The faster she swings, the more kinetic energy she has.

Now consider the swing at its lowest point. At this moment, the child is moving at her maximum speed as she swings downwards. Since kinetic energy depends on speed, this implies that the child has the maximum kinetic energy at this point.

So, the maximum potential energy occurs when the child is at the highest point of the swing's arc, and the maximum kinetic energy occurs when the child is at the lowest point of the swing's arc, primarily because potential energy depends on height and kinetic energy depends on speed.

To calculate the maximum potential energy of the child on the swing, you can use the equation:

Potential energy (PE) = mass (m) x gravity (g) x height (h)

Where:
- Mass (m) is the mass of the child
- Gravity (g) is the acceleration due to gravity (approximately 9.8 m/s^2)
- Height (h) is the vertical distance from the child at the highest point to the reference point (e.g., ground level)

To calculate the maximum kinetic energy of the child on the swing, you can use the equation:

Kinetic energy (KE) = 0.5 x mass (m) x velocity^2 (v^2)

Where:
- Mass (m) is the mass of the child
- Velocity (v) is the speed of the child at the lowest point of the swing's arc

Keep in mind that these equations assume there are no other external forces affecting the child's motion, such as air resistance.

If you provide specific values for the mass of the child, the height, or the velocity, I can help you calculate the exact potential or kinetic energy.