The coefficient of static friction between the tires of a car and dry road is 0.62. The mass of the car is 1600 kg. What maximum breaking force is obtainable (a) on a level road and (b) 8.6° downgrade? The handle of a floor mop of mass m makes an angle θ with the vertical direction. Let μk be the coefficient of kinetic friction between mop and floor and μs the coefficient of static friction between mop and floor. Neglect the mass of the handle. (a) Find the magnitude of the force F directed along the handle required to slide the mop with uniform velocity across the floor. (b) Show that θ is smaller than a certain θ0 of the mop cannot be made to slide across the floor no matter how great a force is directed along the handle. What is angle θ0?