What is the moment of inertia of the earth?

Given that the radius of the earth is 6.38xx10^6"m"6.38×106m and the mass of the earth is 5.98xx10^24"kg"5.98×1024kg.

1 Answer
Aug 15, 2017

I~~9.736xx10^37"kgm"^2I9.736×1037kgm2

Explanation:

If we think of the earth as a solid sphere rotating about its center, the moment of inertia is given by:

color(darkblue)(I=2/5MR^2)I=25MR2

where MM is the mass of the earth and RR is its radius

We are given the following information:

  • |->M=5.98xx10^24"kg"M=5.98×1024kg
  • |->R=6.38xx10^6"m"R=6.38×106m

Substituting these values into the equation above:

I=2/5(5.98xx10^24"kg")(6.38xx10^6"m")^2I=25(5.98×1024kg)(6.38×106m)2

=>=2/5(5.98xx10^24"kg")(4.07044xx10^13"m"^2)=25(5.98×1024kg)(4.07044×1013m2)

=>2/5(2.4341xx10^38"kgm"^2)25(2.4341×1038kgm2)

=>color(darkblue)(=9.736xx10^37"kgm"^2)=9.736×1037kgm2