A fireman of mass 60 kg slides down a pole. He is pressing the pole with a force of 600 N. The coefficient of friction between the hands and the pole is 0.5, with what acceleration will the fireman slide down (g = 10 m/s 2) (a) 1 m/s 2 (b) 2.5 m/s 2 (c) 10 m/s 2 (d) 5 m/s 2