Bliver man mindre våd, hvis man skynder sig gennem regnen?

I made a mathematical proof of this in my first year physics class, the only difficulty lies in the definition of "wet." First, simplify the human form as a cube (this works thanks to our relative symmetrical form. Even if we were highly assymetric, the answer would still hold, there would just be an optimal body orientation involved.) Now, look at the rain as a vector field. Again, we can simplify things and say the rain has a constant velocity. This is actually a fairly accurate representation of rainfall, barring gusts of wind and sudden downpours.. Finally, take the flux thru the cube of the falling rain, using vector calculus. To make the cube "run", simply apply the opposite velocity to the rains vector field. This proof quickly shows that regardless of what you do, you get the same amount of rain from directly above. However, moving will effect how much rain you impinge on your sides. (makes sense, good.) For a vertical rain shower, you actually stay driest standing still. For slanted rain, you should match the horizontal component of the rain exactly. Any other movement from this axis has no effect. As well, you should NOT accelerate, tho most humans have a hard time doing that for more than a second or two, we tend to run at a constant velocity. Now, when I said "driest", I meant you have the least amount of "rain flux" thru your box. But you will continue to gain flux with time. So if there is a nearby shelter, and the rain isnt going to stop, you should head towards it. If not, just stand still or match the rains velocity. Funny enough, this is almost exactly the behavior that cows show in a field. (they will stand stock still if there is no barn, otherwise they head for shelter.) Now, the whole crux of the problem really lies on the definition of "wet." How much rain makes you wet? At one point are you completely soaked and cannot get more wet? Thats a bit harder to define, and most people, even given the definitions to those variables, arent going to do the calculations required to deduce the optimal "stay dry" strategy given the rains velocity and the proximity of local shelter; they just run for it.

Denne nyhed er da en ældre sag ?

 

Nyeste kommentar er fra 2009 , jeg kan også huske at have set dette indlæg før...

 

Mvh Finn

Tak for det Jonas....

 

Jeg checkede ikke lige div. grafik boxe, læste kun artiklen :-)

 

Så ... ny trend... "For et år siden" à la EB's....

 

Mvh Finn Østervig