Question

In the Biomedical and Physical Sciences building at MSU there are 135 steps from the ground floor to the sixth floor. Each step is 16.0 cm tall. It takes 5 minutes and 40 seconds for a person with a mass of 63.9 kg to walk all the way up. How much work did the person do? What was the average power performed by the person during the walk?How many food Calories did the person burn during the walk? (1 Cal = 4.1868 kJ)

Answer 1

height, h=135*16 cm = 21.6 m
Time taken, t= 5 min 40 sec
= 340 seconds
mass, m= 63.9 kg
g=9.81 m/s²
(note that all values are in SI units)
Work done, W = mgh J (joules)
= 13540.2 J
(multiply together m,g & h to get work done)
Power = work done per second, so
= W/t J/s
=13540.2 J/340s
=39.82 J/s (or watts)

Each Cal = 4.1868 kJ
= 4.1868*1000 J
= 4186.8 J (joules)
Number of food calories
= W/4186.8 Cal.
= 3.234 Cal.