Current Attempt in Progress A 72 kg firefighter slides, from rest, 4.2 m down a vertical pole. (a) If the firefighter holds onto the pole lightly, so that the frictional force of the pole on her is negligible, what is her speed just before reaching the ground floor? (b) If the firefighter grasps the pole more firmly as she slides, so that the average frictional force of the pole on her is 510 N upward, what is her speed just before reaching the ground floor? (a) Number i Units (b) Number Units