several misc. questions: open wounds, solubility, diffraction, polarization

[blankmoniker]

i'm having one of those major brain farts and i'm unable to comprehend why the following are true.

would anyone venture to shed light on the following?

1. it's common knowledge that you should elevate open wounds to prevent bleeding. would someone be able to elaborate why using the concepts/equations we use for the mcat?

2. why is blood pressure greater in your calves than in your arm?

3. are we suppose to consider blood viscous or non-viscous fluid for the mcat?

4. does adding more solute to a soln change solubility at all? i would think it would but i have conflicting notes.

5. does adding more solvent -always- increase the dissociation of solute/salt?

6. is it safe to assume that dissolving solutes will always exhibit -G?

7. why dont we consider diffraction for double slit experiments?

8. BR physics (second book) page 261, number 45 state that a mirage could be differentiated from a real object by polarization since refracted light can be polarized. why can't reflected light from a real object be polarized as well?

thx so much in advance!!

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[TieuBachHo]

1. it's common knowledge that you should elevate open wounds to prevent bleeding. would someone be able to elaborate why using the concepts/equations we use for the mcat?
--- When you pump blood upward, you have a negative acceleration and vice versa. Also, the fluid on top will have lower pressure due to weight.

2. why is blood pressure greater in your calves than in your arm?
--- In addition to explanation in 1., the blood passage's diameter counts. If you apply the same pressure, the one with a larger cross sectional area will have higher pressure.

3. are we suppose to consider blood viscous or non-viscous fluid for the mcat?
--- I think it depends on the particular passage.

4. does adding more solute to a soln change solubility at all? i would think it would but i have conflicting notes.
--- Every soln has a saturation point. What is solubility? Does it change by adding more solutes or diff. solutes?

5. does adding more solvent -always- increase the dissociation of solute/salt?
--- When the soln is over-saturated.

6. is it safe to assume that dissolving solutes will always exhibit -G?
--- Does it occur spontaneously or non- spontaneously?

7. why dont we consider diffraction for double slit experiments?
--- Like what? Give example.

8. BR physics (second book) page 261, number 45 state that a mirage could be differentiated from a real object by polarization since refracted light can be polarized. why can't reflected light from a real object be polarized as well?
--- I don't have this book.

 

[Danlee07]

1 & 2. P=density*g*h, is larger. Use arms to the level of the heart to do Bernoulli's P1 + rho*g*h1 = P2 + rho*g*h2. I don't really think the acceleration has anything to do with this... otherwise we'd all be in trouble. Simply put though... your calves are further from your heart so it's affected more by gravity.
3. Blood's not supposed to be an ideal fluid so it's most likely viscous.
4. well yeah, just not past the saturation point.
5. oversaturation. you can do it with either because remember that the intramolecular has to beat out the intermolecular.
6.yeah, if you want a thermodynamically favored reaction
7. Slit width in double slits are so tiny that realistically, measuring would make measurements less practical than different measurements. you get a missing maxima (3rd) as well.
8. you state refracted but ask reflected...Idk which one.