Question

Would earth orbiting the sun be known as

A. Newton’s First Law of Motion

B. Newton’s Second Law of Motion

C. Newton’s Third Law of Motion

Answer 1

All three of Newton's laws of motion, as well as his law of universal gravity, are involved in the explanation of orbits.

Answer 2

C. Newton’s Third Law of Motion.

Because...
Newtons third law implies conversation of momentum it can also be seen as following from the second law: when one object pushes a second object at some point of contact using an applied force, there must be an equation of opposite force from the second object that cancels the applied force. Otherwise, there would be a nonzero net force on a massless point which, by the second law, would accelerate the point of contact by an infinite amount.