Seen in a doctor's office (admittedly as an ad for an insole):
"Your feet absorb about a 1000 tons of force every day."
Having nothing better to do while waiting, I wondered what this might
mean. Ignoring the fact that a single impulse with a peak force of
1000 lbs (say) would certainly not be physiologically equivalent to
10 impulses of 100 lbs each, it presumably must be some kind of Fermi
estimate to the effect of a sum over (kind of event) * (force due to
that kind of event). If so, this excludes continuous standing (which
would require some kind of integration rather than a discrete
summation) and probably refers to walking. Assuming an average human
weight of 150 lbs and step size of 2 feet, you come up with the
advertised number if you walk a total of 5 miles per day. I suppose
that's plausible but of questionable value on its own.
Challenge: How would you rephrase the original statement to make it
more meaningful and useful?
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Carl E. Mungan, Asst. Prof. of Physics 410-293-6680 (O) -3729 (F)
U.S. Naval Academy, Stop 9C, Annapolis, MD 21402-5026
mungan@usna.edu http://physics.usna.edu/physics/faculty/mungan/