Weight Loss Physics Before SR: How Was It Understood?

pantheid
Messages
53
Reaction score
0
People jog, thereby expending energy, and lose weight because of it. As modern people who understand mass energy equivalence, we know (or can presume) that during the process of running, the body derives its kinetic energy by breaking down ATP in the cells. When this breakdown occurs, the total mass present decreases and eventually the person loses significant amounts of weight (please let me know if anything here is factually incorrect).

Since people have known for millennia that running leads to weight loss, how was it explained before E=mc^2.
 
Physics news on Phys.org
pantheid said:
(please let me know if anything here is factually incorrect).

Your whole premise is incorrect. Weight loss due to exercise has nothing to do with mass-energy equivalence; the mass equivalent of the energy consumed during exercise is many orders of magnitude too small to account for weight loss. The question of how exercise leads to weight loss is a question about physiology, not physics. Thread closed.
 
OK, so this has bugged me for a while about the equivalence principle and the black hole information paradox. If black holes "evaporate" via Hawking radiation, then they cannot exist forever. So, from my external perspective, watching the person fall in, they slow down, freeze, and redshift to "nothing," but never cross the event horizon. Does the equivalence principle say my perspective is valid? If it does, is it possible that that person really never crossed the event horizon? The...
ASSUMPTIONS 1. Two identical clocks A and B in the same inertial frame are stationary relative to each other a fixed distance L apart. Time passes at the same rate for both. 2. Both clocks are able to send/receive light signals and to write/read the send/receive times into signals. 3. The speed of light is anisotropic. METHOD 1. At time t[A1] and time t[B1], clock A sends a light signal to clock B. The clock B time is unknown to A. 2. Clock B receives the signal from A at time t[B2] and...
From $$0 = \delta(g^{\alpha\mu}g_{\mu\nu}) = g^{\alpha\mu} \delta g_{\mu\nu} + g_{\mu\nu} \delta g^{\alpha\mu}$$ we have $$g^{\alpha\mu} \delta g_{\mu\nu} = -g_{\mu\nu} \delta g^{\alpha\mu} \,\, . $$ Multiply both sides by ##g_{\alpha\beta}## to get $$\delta g_{\beta\nu} = -g_{\alpha\beta} g_{\mu\nu} \delta g^{\alpha\mu} \qquad(*)$$ (This is Dirac's eq. (26.9) in "GTR".) On the other hand, the variation ##\delta g^{\alpha\mu} = \bar{g}^{\alpha\mu} - g^{\alpha\mu}## should be a tensor...
Back
Top