The Moon orbits Earth in an average of p = 27.3 days at an average distance of a =384,000 kilometers. Using Newton’s version of Kepler’s third law determine the mass of Earth. You may neglect the mass of the Moon in comparison to the mass of Earth.

Answer :

Answer:

The mass of the earth, [tex]M=6.023\times 10^{24}\ kg[/tex]

Explanation:

It is given that,

Time taken by the moon to orbit the earth, [tex]T=27.3\ days=2358720\ m[/tex]

Distance between moon and the earth,[tex]r=384000\ km=384\times 10^6\ m[/tex]

We need to find the mass of the Earth using Kepler's third law of motion as :

[tex]T^2=\dfrac{4\pi^2}{GM}r^3[/tex]

[tex]M=\dfrac{4\pi^2r^3}{T^2G}[/tex]

[tex]M=\dfrac{4\pi^2\times (384\times 10^6)^3}{(2358720)^2\times 6.67\times 10^{-11}}[/tex]

[tex]M=6.023\times 10^{24}\ kg[/tex]

So, the mass of the earth is [tex]6.023\times 10^{24}\ kg[/tex]. Hence, this is the required solution.

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