Newton concluded that some force had to act on the moon because
A) a force is needed to keep the moon in motion.
B) a force is needed to pull the moon outward.
C) a force is needed to pull the moon away from straight-line motion.
D) the moon moved at a constant velocity.
E) all of the above

Question

Quizplus · Accepted Answer

Newton concluded that a force is needed to pull the moon away from straight-line motion, which is the gravitational force exerted by the Earth, causing the moon to orbit the Earth rather than moving in a straight line.

Newton Concluded That Some Force Had to Act on the Moon