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Physics & kinda biology


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Alright i was thinking about how cold my hand's get on my motorbike even with thermal gloves on and somehow i come up with an analogy to do with physics thats kinda confusing me.


Basically if im on my motorbike doing say 60mph (96km) and inside my body my hearts pumping the good stuff so the blood is getting to my hands at 2 foot per second, would the force of my motorbike going left on the x axis have any effect on the blood which is trying to move at 1 foot per second right on the x axis?


im guessing this has something to do with force


im thinking if the blood gets slowed down by the opposed pressure while trying to get to the intended cells then this force would be canceled by the suction it feels when the blood coming back on itself is being being accelerated by the stated opposed force so essentially balancing itself


or is the force of no consequence?



http://en.wikipedia.org/wiki/Blood_flow <--- too much physics for biology :P

Edited by keelanz
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unless your accelerating the forces on your blood at 60mph are the same as at 0mph.


this is all about heat transfer what needs to happen is to reduce the flow of heat from your hands to the outside.


you can do this by using thermally resistive gloves(which you say you have done) but you could increase this by forming a boundary layer around the glove (making the gloves thicker would work but then you wouldn't be able to control the bike).


Basically, you want to get yourself a pair of furry(on the outside) gloves.


the fibers will keep a bubble of relatively stagnant air moving with your hand and reduce the convective heat transfer.

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IA is correct.


An important factor is the surface ratio under contact with cold air. If you keep your hands closed, the ratio diminishes. While riding your bike, your hands are constantly open, not a good thing.

Under this aspect, mittens are better because fingers touch, but maybe it is not a good idea for secure riding.


An old mummy's trick for cold hands is to boil an egg just before leaving home and keep it hot in your pocket.





Under difficult circumstances, put your hands in the warmer parts of your body. Not your mouth, but your genitals.

Edited by michel123456
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so if i got this right, you guys are saying the force of direction x has no effect on the force going in direction y?


i think perhaps i presumed speed itself was a force, in my head my analogy still makes sense because as your body is moving --> that way; the force would push <-- that way regardless of acceleration even though acceleration would increase the force massively the force seems to exist, is this only external? I.E the force of air pushing my body?

Edited by keelanz
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No, the forces have little to nothing to do with blood circulation. Only if the forces would be very extreme (i.e. more than 2-3 G for long periods, or more than 6-10 G for a short period) it would matter... but you cannot achieve such forces on a motorbike. You need a jet fighter or a stunt aircraft for that.


You lose heat because of the heat transfer. As was mentioned by insane_alien, the only parameter that you can influence easily is the quality of the gloves, and perhaps the outside surface area of your hand/fingers (mittens is better than gloves, and a fist is better than an open hand).


However, if you have gloves that are a little too small, you can prevent proper blood circulation. That can also have an effect. You need some blood circulation even if you have the thickest gloves in the world. Could it be that your grip on the throttle is too tight? I can imagine that you do not get good blood circulation if you have a really tight grip for a long time.

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