Assertion: body's force | /r/HasProperty | necessary
Facets:
value: to keep an object
type: PURPOSE
value: to change motion
type: PURPOSE
Source sentences:
text: Galileo Galilei, however, realised that a force is necessary to change the velocity of a body, i.e., acceleration, but no force is needed to maintain its velocity.
text: Calculating the lifting force can tell you how much force is needed to send these objects airborne.
text: He realized that bodies that are uninfluenced by forces continue indefinitely to move and that force is necessary to change motion, not to maintain constant motion.
text: Moving objects, so it was believed, would eventually stop moving; a force was necessary to keep an object moving.
text: One implication is that no force is required to keep an object moving regardless of the velocity; force is needed only to change its velocity.