(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

What is the Kinetic Energy of the Earth Orbiting Around the Sun in Joules?

2. Relevant equations

E rotation = (1/2)* I * w^2

where I = moment of Inertia

where w = angular velocity

3. The attempt at a solution

Well, this is my predicament: I don't know whether my professor wants me to use the above equation or not, but I don't know any other way to solve it. My answer is comes out to somewhere around 10^29, while his is around 10^33. So obviously something must be wrong....

My solution:

Earth's period = 23.93 hours

Therefore, its angular velocity is 7.29×10^ -5 rad·s-1.

Assuming that the Earth is perfectly spherical and uniform in mass density, it has a moment of inertia, I = 9.72×10^37 kg·m2.

Therefore, it has a rotational kinetic energy of 2.58×10^29 J.

Is this right? Or am I missing something completely?

Thanks a lot.

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# Homework Help: Rotational Kinetic Energy Question (Regarding the Earth)

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