Question

The period of revolution of a planet around the sun depends on the radius of the orbitR, the mass of sun M and the gravitational constant G. From dimensional considerations obtain the Kepler’s law of periods of the planetary motion.

Answer 1

The laws can be stated as below:(a) Kepler’s first law (law of elliptical orbit):- A planet moves round the sun in anelliptical orbit with sun situated at one of its foci.(b) Kepler’s second law (law of areal velocities):- A planet moves round the sun in such a way that its areal velocity is constant.(c) Kepler’s third law (law of time period):- A planet moves round the sun in such a way that the square of its period is proportional to the cube of semi major axis of its elliptical orbit.T2 ∝ r 3Here R is the radius of orbit.T2 = (4π2/GM) r 3  i hope this ans is correct