Question

How would you calculate the speed at which the earth revolves around the sun in m/s?

Answer 1

Calculate from the average distance of the Earth from the sun and the time it takes to complete one orbit as about `3xx10^4 ms^(-1)`

Explanation:

The average distance of the Earth from the Sun is spproximately `150` million km or `1.5 xx 10^11m`

The orbit of the Earth around the sun is roughly circular (more eliptical really, but let's keep it simple), with a period of roughly `365` days.

So the path that the Earth traverses in `365` days is approximately the circumference of a circle of radius `1.5 xx 10^11m`.

Use the formula `C = 2pir` to find that this is about `9.4 xx 10^11m`.

The number of seconds in `365` days is:

`365 * 24 * 60 * 60 = 31536000`

So the tangential velocity of the Earth is approximately:

`(9.4 xx 10^11) / (3.1536 xx 10^7) ~~ 3 xx 10^4 m s^(-1)`

That is `30` km per second.

If you want more accuracy, get more accurate figures for the distance of the Earth from the sun at perihelion/aphelion and use a more accurate figure for the orbital period.