Monday, December 06, 2010

Friday's Siesta Fermi Problem Solution

Fermi Problem Solution:

First, according to a doctor at the siesta competition, less than 30 percent of the contestants actually fell asleep. To make our lives easy, we'll say 100 people (roughly 28 percent) fell asleep.

Next, we'll assume that it took the average napper 10 minutes to fall asleep. Normally, people might average a longer drifting off time, but we're assuming these people are expert nappers capable of falling asleep quickly.

Multiplying those two numbers together, we can say that the total amount of napping done in the contest was 1,000 minutes.

Assuming each of the nappers works an office desk job, each would ordinarily burn 102 kilocalories (kcals) an hour at work. Over ten minutes, those 100 office workers would burn a combined 1699 kcals. Since a person burns about 61 kcals an hour while sleeping, we guess a collective 1016 kcals were burned by the nappers.

By subtracting the number of kcals burned while sleeping from working, we know that the net energy the nappers conserved was about 683 kcals, or 2.9 million Joules.

That's enough to power the average U.S. home for an hour!

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