Answer to Question #167888 in Physics for Nebiyu

Question

 State kepler’s laws of planetary motion.

Answer 1

1. 1st law: The orbit of a planet is an ellipse with the Sun at one of the two foci.
2. 2nd law: A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
3. 3rd law: The square of a planet's orbital period $T$ is proportional to the cube of the length of the semi-major axis of its orbit $a$:

$$\dfrac{T^2}{a^3} = const$$