I've been reading the book Relativity by Einstein, but need some things cleared up. I have only studied physics in college (took both mechanics and topics pertaining to more smaller scale phenomenas) and have a vague familiarity with concepts of physics but would like to expand on this a bit more. So here are my questions so far: -I am assuming that every object has an absolute velocity; am I right? -We measure kinetic energy with respect to a rigid body such as that of the earth. Do I possess kinetic energy at this moment in which the earth is moving? That is I am moving at a certain velocity even if I am at rest with respect to the earth. How can the measurement of kinetic energy be accurate then? -I am not quite sure what Einstein was intending to explain near the beginning of the book with Gallaien coordinates.