A child's wagon with rubber tires is being pulled along a street. The wagon and its load have a combined mass of 28.0 kg. The coefficient of friction for rubber on dry asphalt is 0.70. a) Find the force of friction. (2 marks) b) How large must the pulling force be in order to get the wagon to accelerate at 0.50 m/s [forward]? (3 marks) c) Assuming that the wagon starts from a rest position, find its displacement after 22.0 s. (3 marks)