Physics - Gravitation Question with Solution | TestHub
Every planet revolves around the sun in an elliptical orbit :
A. The force acting on a planet is inversely proportional to square of distance from sun.
B. Force acting on planet is inversely proportional to product of the masses of the planet and the sun.
C. The centripetal force acting on the planet is directed away from the sun.
D. The square of time period of revolution of planet around sun is directly proportional to cube of semi-major axis of elliptical orbit.
Choose the correct answer from the options given below :
Options:
Answer:
Solution:
Newton's law of gravitation state that gravitational force between two point masses is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. It is stated as
A planet moves around the sun in a circular path for which the gravitational force of attraction on the planet by the sun provides the necessary centripetal force. This centripetal force is always directed towards the centre of the sun at each point of its path which is responsible for circular motion of planet.
From Kepler's Third Law, we know that the squares of the orbital periods of the planets are directly proportional to the cubes of the semi-major axes of their orbits.
Thus, A and D only are correct.