Newton's First Law states that "every body continues in its state of rest, or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it."

Work is said to be done when the point of application of a force moves in the direction of the force.

Everything continues in a state of free fall unless an intervention is made to change that free fall.

The intervention has to be justified, in the sense that the free fall after the intervention has to be in some sense better than it would have been had the intervention not occurred.