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Re: Why do we care about heat?



John Mallinckrodt wrote:

... If *you* haul a weight from height H = 1m to H = 2m in the real
world *you* have just performed an irreversible process for a number of
reasons.

At 07:12 11/1/99 -0500, John Denker replied:

OK, how irreversible is it? What percentage of the work *must* be done
irreversibly? Can you state a positive lower bound?

Hmmm....where to start?

For my purpose, I will suppose that 'reversible'
implies 100% efficient.

a 2000 Calorie p.d diet (=8.4MJ)
a 120 watt output capability at the 12 hour rate (??)
120 X 12 X 60 X 60 = 5.2MJ

Efficiency = 100 X 5.2/8.4 = 62%


Hehehe...I hope this started your day with a smile. :-)


brian whatcott <inet@intellisys.net>
Altus OK