Re: Gasoline prices

["Bernard G. Cleyet & Nancy Ann Seese" <georgeann@REDSHIFT.COM>]

I heard somewhere that an apple has enuff energy to "power" some one to swim a mile.  Outrageous.  Here are my "off the cuff" assumptions.  1/10 hp to swim a mile in 20 min.  (3 mph).  25 food cal in
an apple (25K cal or Cal.)  1/10 hp is ~776/10 Watt for 20 X 60 s (1200 X 776 / 10 ~ 100k J.)  25 k caL. X 4.2 J/CAL ~ 100 K J.   Voilla,  EXCEPT assumes 100% efficiency;  someone else has to take it
from here.


bc

P.s. one loses weight from exercise not by "burning" the food, but my reducing the intake (calibrates the appestat), and by raising the basal metabolism.


Doug Craigen wrote:

> > Table 1.  Passenger-Moving Efficiencies Of Different Human
> > Transportation Modes, In Passenger-km/megajoule:
> > Human on bicycle                        18.0   pass-km/MJ
> > Human walking                     5.0
> > Intercity railroad train                  1.7
> > Urban bus                         0.9
> > Carpool auto (occupancy=4)        0.7
> > Commercial airplane               0.4
> > Commuting auto (av occ=1.15)      0.2
>
> I remember an exam where I stared for ages at a question something to
> the effect: "which is better, a gas engine or an electric motor" (no
> application was mentioned).  While I thought I knew what the "right"
> answer was, it just wasn't a fair question.  One needs to work a bit to
> formulate an apples:apples type of comparison.
>
> The numbers above are interesting, but they lead to many more
> questions.  The first thing I wondered about was whether the energy
> figures for a human refer to fat burned or food consumed.  Exercise
> figures usually mean fat burned, but a cost-benefit analysis would have
> to be referenced to how much you ate.  Here would be some interesting
> apples:apples comparisons...
>
> How much would it cost in groceries to buy the food that would enable
> you to cycle 100 km?  Compare that with the cost of gas to drive 100 km.
>
> In the consumption of the food above, a certain amount of "waste" is
> produced.  How does this compare with the pollution generated by the
> car?
>
> ... one could go on.  I have no idea whether this would make a bicycle
> look better or worse than the above table, but I would be interested
> because I find these sorts of comparisons more meaningful.
>
> \_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/
>
> Doug Craigen
>           http://www.dctech.com/physics/