Calculate the torque required to accelerate the Earth in 3 days from rest to its present angular speed about its axis(adsbygoogle = window.adsbygoogle || []).push({});

I got that the Earth's mass is 5.98 X 10^24 kg and its radius is 6.38 X 10^6 m.

I used that the earth is solid sphere with a moment of inertia of:

I = 2/5*M*r^2 so then the Earth's moment of inertia would be: 9.74 X 10^37 kg*m^2.

To get torque i used T=(alpha)I, alpha being dw/dt, so I used (alpha)=(2pi)/(259200 s). 259200 seconds in three days.

I get the wrong torque, so what is wrong?

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# Homework Help: Torque needed to accelerate Earth

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