1. The problem statement, all variables and given/known data The car's wheel with mass 1kg and radius 0.3m has initial speed 40rad/s. When braked, the force push to the center of the wheel is 10N. The car stops after 2s. Find coefficient. 2. Relevant equations 3. The attempt at a solution This is what I did Fc= Us.N= Us*m*g so Us= Fc/mg But why the problem gives so many information..about velocity..?