Xian

When I bend my fingers, there is always a bend at both knuckles. I'd like to learn how to bend my fingers only at the first knuckle (proximal interphalangeal articulation, or PIP joint). Being able to do it only on the second knuckle would be cool too and would be a plus if you guys/gals could explain that. Anyways, anyone know a way that I could learn to bend my fingers that way? The reason I wanna learn this is so I can learn to do pen tricks lol.

Ok, so wikipedia says that oobleck and all dilatants increase their viscosity in response to the rate of shear. Now from what I understand, shear stress is a force tangential to the surface of the substance and thus the shear rate is the time derivative of shear stress. Now my questions is that when I whip up some Oobleck, I can hit it with a normal force and it will still respond with a sudden increase in viscosity. This is an obvious truth so why does wiki say in several articles that it responds to shear rate? Also, is it the actual force involved or would something moving at a constant velocity also have a similar effect? And of course the all around question of why does it work this way? Thanks in advance guys.

Ok, so 3 years ago I was involved in wrestling and tae kwon do. Loved the sports. I wanted to get stronger so I started training my bones so that they could take stronger blows. I overestimated the extent of my training one day and messed up my knee. The knee pain was really bad (especially when i squatted down) so I had to quit tae kwon do (wrestling was over and my new school didn't offer it so that was solved as well). Got an X-ray and the docs told me I had a bone marrow edema in my knee (still not too sure what that is).

Flash forward three years later and I wanna get off my butt and start training again but my knee acts up a little bit after my training session (which involves a lot of kicking). I wanna know how I should deal with this knee thing, if its okay to train at this stage, how much longer this condition will last and if I'll ever be back to normal. Am I further damaging my knee? Is there some simple therapy I can apply every day to speed up my recovery and/or minimize the risk?

Thanks in advance guys and gals.

I'm being told more often nowadays that when one gets a new portable product with a rechargeable, one should first discharge the battery all the way down to zero, then recharge to max, then repeat for 2 or 4 times. Why do rechargeable batteries have to go through this process?

So yea, like I said, I stand up to stretch out and once I'm done, something sometimes happens. As soon as I get out of "stretching mode" i feel a little light headed and then I feel blood pumping into my head, harder and harder and harder, until it peaks out and then subsides. Is there a reason for this? Is it normal? What can I do about it (besides not stretching)?