Question

3. The speed of revolution decreases if the distance between the sun and earth
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Answer 1

Answer:

Kepler's 2nd Law: A line connecting the Sun and planet sweeps out equal areas in equal times. That is, the orbital speed of any one planet varies inversely with its distance from the Sun (actually, orbital speed varies inversely with the square-root of the distance, but you needn't worry about that detail).

Answer 2

The speed of revolution decreases if the distance between the sun and the earth increases.

This can be explained using Kepler’s second law.

• It is observed that as the earth gets closer to the sun, the earth move faster because the gravitational pull from the sun get stronger.

It can also be explained using Kepler's third law,

• According to Kepler’s law of periods,” 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”. $T^{2}$ ∝ $a^{3}$

As the distance between sun and the earth increases, the time taken for the revolution increases and as we know that speed is inversely related to time hence speed decreases.