One kilogram of fat is equivalent to 30 MJ of energy. The efficiency of converting fat to mechanical energy is about 20%. a) Suppose a 75 kg person runs up the stairs of tall building with a vertical height of the 450 m, how much work is done by the person? b) If all the energy used to do the work comes from "burning" fat, how much fat is used up by the exercise? c) If the person took 45 min. to run up the stairs, what was their power output. My proof: A. m= 75kg d= 450m w=75kg(9.8N/kg)*450m w=3.3*10^5J PLZ HELP ME IN B AND C AND TELL ME A IS RIGHT OR WRONG.