Question

the planets in our solar system orbit the sun due to the force of gravity. what would happen to the motion of these planets if the suns gravitational pull suddenly disappeared? a. the planets would move in straight lines away into space. b. the planets would fall toward the sun. c. the planets would stop moving completely. d. the planets would continue orbiting as usual.

Explanation:

According to Newton's first law of motion, an object in motion will continue in motion with the same speed and in the same direction unless acted upon by an unbalanced force. Planets orbiting the Sun have a tangential velocity. The Sun's gravitational pull acts as the centripetal force that keeps them in orbit. If this gravitational pull (centripetal force) suddenly disappears, there is no unbalanced force to change their motion. So, they will move in a straight - line path (tangent to their original orbit) at a constant speed.

• Option B is incorrect because without the Sun's gravity (which was the force pulling them towards the Sun), they won't fall towards the Sun.
• Option C is incorrect as there is no force mentioned that would make them stop (Newton's first law: no external force - no change in motion from moving state).
• Option D is incorrect because the gravitational force (centripetal force) that was responsible for the orbital motion is gone.

Answer:

A. The planets would move in straight lines away into space.