See, we are going to continue our talk on the dynamic equations of motion. Actually, Last lecture we ended up getting this newton equation in this way, I will add those extra terms later on. See this well of course, the equation if I the origin at center of Gravity but, if my origin what located at some other distance and typically if I thought. r G to be X G 0 0. Because, normally you would always choose body coordinate at a distance with X G.