An 82-kg fireman slides 5.2 m down a fire pole. He holds the pole, which exerts a 550-N steady resistive force on the fireman. At the bottom, he slows to a stop in 0.45 m by bending his knees.
Determine the acceleration of the fireman while stopping. Express your answer with the appropriate units. Enter a positive value if the acceleration is downward and negative value if the acceleration is upward.