# college physics

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Estimate the rotational kinetic energy of Earth, assuming it to be a solid sphere of uniform density.

• college physics -

the equation used here i believe is

K=1/2lw^2

k=KE due to rotation
l=moment of inertia about rotation axis
w=angular velocity

l=2/5mr^2

m=mass of sphere

you have to look up all these numbers i believe
i found the mass of the earth to be:
5.97*10^24kg
6.37*10^6m or 6371 km
and the angular velocity to be:

plugging that all in i believe is how you estimate the rotational KE. let me know what you get and we'll compare.

• college physics -

hey..i got 5.52940206x10^26

is that what you got? what are the units?

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