1) Assuming an adult person has an average mass of m=80 kg, and assuming it takes about 30 seconds to climb 5 meters of stairs, the energy used by the person is
[tex]E=mgh=(80 kg)(9.81 m/s^2)(5 m)=3924 J[/tex]
So the power output is
[tex]P= \frac{E}{t}= \frac{3924 J}{30 s} \sim 130 W [/tex]
And since the estimate we made is very rough, we can say that the power output of the person is comparable to the power output of the light bulb of 100 W.
2) Based on the results we found in the previous part of the exercise, since the power output of the person is comparable to the power output of 1 light bulb of 100 W, we can say that the person could have kept burning only one 100-W light bulb during the climb.
