1. The problem statement, all variables and given/known data In describing a wheel's circular motion: "Circular motion arises purely from the resistance of the ground upon which it is applied…this resistance is equal to the force which draws the wheel in the right line" 2. Relevant equations F=m(v^2/r) 3. The attempt at a solution Is this talking about how the only forces acting on the wheel is the normal force and gravity, thus making the centripetal force? How is this equal to the force which draws the wheel forward in linear motion?