In my textbook there is a question that is as follows:- If earth stops rotating about it's own axis,the increase in its temprature will be(Here R=radius of earth,ω=angular velocity of earth,J=mechanical equivalent of heat,C=average specific heat capacity of earth) Here i have doubt why heat is produced if earth stops rotating?and please explain how to solve it.
I agree with the comments of @G.Smith and @Pounik. I'm thinking that one possible explanation as to why the temperature of the earth might increase is due to the inertia of the molten core. The crust would stop but the molten core would continue to rotate. This would result in friction between the molten core and the crust which, in turn, might raise the temperature at the interface. But I must admit, this is purely speculation on my part.
Anyways, as possible food for thought, I hope this helps.