Item NG006005: When a pine cone falls from a tree, its gravitational potential energy decreases and its motion energy increases because its gravitational potential energy is transformed into motion energy.

A pine cone is falling from a tree. How and why do the gravitational potential energy and kinetic energy (motion energy) of the pine cone change as it falls to the ground?

  1. Its gravitational potential energy decreases, and its motion energy increases because its gravitational potential energy is converted into kinetic energy.
  2. Its kinetic energy decreases and its gravitational potential energy does not change because the motion energy of the pine cone is used up as it falls and is not converted into gravitational potential energy.
  3. Its gravitational potential energy and kinetic energy do not change because, regardless of what happens to the pine cone, one form of energy cannot be converted into another form of energy.
  4. Its gravitational potential energy and kinetic energy do not change because while the pine cone is falling, it does not have any gravitational potential energy to be converted into kinetic energy.