http://imageshack.com/a/img923/733/FJKAqj.jpg so here is the deal. is rolling resistance N+Ft or are they "separate" in a means of: N part is for static friction = mu*N and Ft is part of rolling resitance=coefficient of rolling resistance*Ft so that in order for tire to start rolling without slipping do I need to apply such force that overcomes Ft*coeff of rolling resistance. but at the same time that applied force has to be less than mu*N? 2. is N equal for every point from point C to B (see picture) and why? 3. why its the point of most interest just point B (like in this picture, and similar ones explaining rolling friction)?