Question

A child is swinging back and forth on a swing. Changes in her kinetic and potential energy are happening each moment. At which point, or multiple points, in her swinging would each of these two types of energy be at a maximum?

a. At the highest point, potential energy is maximum. At the lowest point, kinetic energy is maximum.
b. At the lowest point, potential energy is maximum. At the highest point, kinetic energy is maximum.
c. Both potential and kinetic energy are maximum at the midpoint of the swing.
d. Both potential and kinetic energy are constant throughout the swing.

Answer 1

The highest point of the swing has maximum potential energy and zero kinetic energy, while the lowest point has maximum kinetic energy and minimum potential energy.

Step-by-step explanation:

When a child is swinging on a swing, there is a continuous transformation between kinetic energy (the energy of motion) and potential energy (the energy of position). At the highest point of the swing, the child has the most gravitational potential energy because she is furthest from the ground. At this point, her movement is momentarily stopped before reversing direction, making her kinetic energy zero. Contrarily, at the lowest point of the swing, her potential energy is at its minimum because she is closest to the ground and moving at her fastest speed, which results in her kinetic energy being at its maximum. Therefore, the correct answer is a. Kinetic energy increases when the child swings downward, potential energy increases when the child swings upward.