Which of these descriptions characterizes the Newtonian understanding of the mechanics of the solar system?
A) The natural motion of the planets is motion in a straight line. The planets are prevented from straight-line motion by the gravitational force of the Sun.
B) The natural motion of the planets is uniform circular motion. The gravitational force of the Sun distorts the orbits of the planets into ellipses.
C) The planets are held in their orbits by a gravitational balance between the Sun (which is closer) and the stars (which are farther away).
D) The planets are held in their orbits by a balance between gravitation (attraction) and magnetism (repulsion).

Question

Quizplus · Accepted Answer

A) Newton's laws of motion and his law of universal gravitation imply that the natural motion of an object in the absence of a force is a straight line at constant velocity. The gravitational force of the Sun alters this straight-line motion, causing the planets to orbit the Sun.

Which of These Descriptions Characterizes the Newtonian Understanding of the Mechanics