The fastest time for the Sears Tower (now Willis Tower) stair climb (103 flights, or 2232 steps) is about 20 min.
a) Estimate the mechanical power in watts for a top climber. Assume the mass of climber is 80 kg and the heigth of the step is 0.18 m.Express your answer to two significant figures and include the appropriate units.
b) If the body is 20% efficient at converting chemical energy into mechanical energy, approximately how many joules and kilocalories of chemical energy does the body expend during the stair climb? Note: 1 food calorie = 1 kilocalorie = 4186 J. Express your answer using two significant figures.