The book I'm reading on special relativity is a ficitonal conversation between Newton and Einstein. Einstein is explaining relativity to Newton. Its a very good book in my unprofessional opinion, but one thing I'm having problems with is energy-mass equivalence. I'm not having trouble with the concept, but the equation. In the chapter, Newton has just learned of relativistic mass increase, so he is trying to modify his old energy equation E=1/2mv squared (sorry I don't know how to make the squared sign lol, could anyone tell me how to do that as well) to work for objects moving at relativistic speeds. In the next chapter Newton comes in to talk about his work he had done during the night, he says that he believes the equation for the energy of an object moving at relativistic speeds is E=Mc squared, where M is the moving mass and the objects speed is so close to c at relativistic speeds he calls the objects speed c. Now the problem I'm having is the book does'nt really explain the math (it was meant for the layman like myself, though I really wanted alittle more detail). It did go on to E=myc squared, and ultimatly E=mc squared for an object at rest. But why, in the equation, was 1/2 the mass dropped for the entire mass? Speed squared was kept but the mass portion of the equation changed. I was hoping someone could tell me why this was done.