Context: In classical physics, an inertial reference frame is one in which an object that experiences no forces does not accelerate. In general relativity, an inertial frame of reference is one that is following a geodesic of space-time. An object that moves against a geodesic experiences a force. An object in free fall does not experience a force, because it is following a geodesic. An object standing on the earth, however, will experience a force, as it is being held against the geodesic by the surface of the planet. In light of this, the bucket of water rotating in empty space will experience a force because it rotates with respect to the geodesic. The water will become concave, not because it is rotating with respect to the distant stars, but because it is rotating with respect to the geodesic.

Question: In classical physics, an inertial reference frame is one in which an object without force does what?
Answer: does not accelerate

Question: What follows a geodesic of space-time?
Answer: an inertial frame of reference

Question: An object in free fall does not experience what?
Answer: force

Question: What holds an object standing on earth against the geodesic?
Answer: the surface of the planet

Question: Why will water become concave, according to the relativity theory?
Answer: it is rotating with respect to the geodesic.

Question: What kind of frame includes objects that do not accelerate when force in applied to them?
Answer: Unanswerable

Question: What does an external frame of refrence follow?
Answer: Unanswerable

Question: What is not experienced by objects moving against a geodesic?
Answer: Unanswerable

Question: What is an object in free fall moving against?
Answer: Unanswerable

Question: What is experienced by objects in free-fall?
Answer: Unanswerable