Question

State and explain kepler's laws of planetary motion. Draw diagrams to illustrate these laws.

Answer 1

First law:

Kepler's first law states that the planets move in elliptical orbits around the sun, with the sun at two foci of the elliptical orbit.

This law means that the motion of the planets around the sun follows an elliptical path, not a circle. As an ellipse has two foci, according to this law, the sun is considered to be situated at one of the foci.

Second law: Kepler's second law states that each planet revolves around the sun in such a way that the line joining the plant to the sun sweeps the equal areas in equal intervals of time.
This law means that a planet while revolving around the sun situated at one of the foci of their elliptical orbit, travels faster when it's close to the sun and slower when it is away from the sun.

Third law: According to this Kepler’s law,” The square of the time period of revolution of a planet around the sun in an elliptical orbit is directly proportional to the cube of its semi-major axis”.

T² ∝ a³ (T is the time period and a is the length of semi-major axis)

Shorter the orbit of the planet around the sun, the shorter the time taken to complete one revolution.