Skip to main content

Free Fall

Define the free fall​

In Newtonian physics, free fall is any motion of an object where gravity is the only force acting on it. In general relativity, gravity is represented as the curving of space-time, not a force, so free fall is any motion of an object where no force is acting on it. During a free fall, the object may look free in the air or in the space, but it follows some unchanging law, which is the target of our investigation.

If we ignore the air resistance, what scenarios below are free falls? Discuss in your group and write down your choice. You can add reasons and clarifications if you deem necessary.

  • An apple falls from a tree.
  • An apple falls inside the water.
  • A person stands on the ground.
  • A helicopter takes off from the ground.
  • A spacecraft circulates the Earth without propulsion.
  • A person jumps off a cliff with a bungee cord.