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Re: [Phys-l] Food Liar's calorie chart



> One can further estimate that 200lb displaced over a mile is
1,056,000 ft-lbs, or 342 nutritional calories (according to one
on-line calculator), yielding a factor mu (F = mu.N) of .43 for
> jogging, and .29 for walking.

Equating body weight with force in the direction of displacement
is suspect on the face of it.

How so? We do it all the time to incorporate friction in kinematics (factor mu, normal force [weight], direction in the line (albeit against) of displacement). Here the dominant effect, to get the walker walking or the jogger jogging, is friction of the shoes against the walking/running surface.

I have also read suggestions that the energetic cost of moving is
proportional more to time than to distance, so that I read of folks
being encouraged to walk at any speed for set time periods
as a slimming strategy.

I've gathered that this is due to the mantra that aerobic exercise is better for slimming strategies, and that certain windows of duration are optimal. In the end though, it is F.x that determines the amount of energy expended.


Stefan Jeglinski