Question

Imagine a light planet revolving around a very massive star in a circular orbit of radius r with a period of revolution t. If the gravitational force of attraction between the planet and the star is proportional to then

Answer 1

Let the mass of massive star be m1 and

mass of planet be m2

the distance between them is given by radius of orbit being equal to t

Therefore according to universal law of gravitation, the gravitational force is given by,

F∝ m1 × m2 / t²

Thus the gravitional force of attraction between the planet and star is directly proportional to product of masses of planet and star and inversely proportional to square of distance between them.