How much work does gravity have to do to keep earth revolving around sun for one cycle.?

Question

What energy(which is work) keep it going for several cycles?

Answer 1

Assuming a perfectly circular orbit for the Earth around the Sun (which is not quite true), no work is done by (or against) gravity. This is because the motion (velocity vector) of the Earth and the force vector of gravity (towards the Sun) are at right angles to each other.

Work done is the product of [the magnitude of the force] and [the component of distance moved in the direction of the force]. There is no movement of the Earth towards or away from the Sun, hence no work is done by or against gravity.

Even when taking the elliptical nature of the Earth's orbit into account, the same amount of work is done by gravity that is done against gravity, hence the net amount of work done is zero, once again.

Answer 2

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