How do the following affect the specific gravity of urine?

Doesn't everything on earth fall at a specific gravity of 9.8 m/s/s?  I'm intrigued by this question.

No, if you're thrown with an initial speed, this could change...

 lol Its urine Specific gravity. It depents from the concentration of solutes in urine. http://en.wikipedia.org/wiki/Urine_specific_gravity (I didn't know it either)


I found this (it is referred to Urine specific gravity) :
"specific gravity is increased in dehydration, pituitary tumor or trauma that causes siadh, decrease in renal blood flow (as in heart failure, renal artery stenosis, or hypotension), glycosuria and proteinuria, water restriction, fever, excessive sweating, vomiting, diarrhea, and x-ray contrast dye.

specific gravity is decreased in overhydration, diabetes insipidus, renal failure, diuresis, hypothermia, glomerulonephritis and pyelonephritis."
(from page 23-26, fluid & electrolyte balance: nursing considerations, 4th edition, by norma m. metheny)"
(source: http://allnurses.com/nursing-student-assistance/urine-specific-gravity-260587.html )

So, I guess a and d are increase,
and b and c are decrease.

What specific gravity is? http://en.wikipedia.org/wiki/Specific_gravity

You really have to think about the underlying process when answering these questions. It will help tie things together  and avoid memorization.
First, what is urine--metabolic wastes and some electrolytes diluted in water, usually.
a) fever
-in fever, you temperature is elevated, your metabolism is high--so metabolic wastes will be higher. You also sweat more, thus losing water with evaporation. Essentially, your body is making more waste while losing the diluent, making "final product", so to speak, more concentrated, hence higher specific gravity
b)diuretic
-this one is easy. A diuretic will just make you lose a lot of water (with some electrolytes), but the proportion of water loss is much higher than normal--that's the purpose of a diuretic. The body does not nave enough time to "fill" the outgoing water with metabolic products, so urine comes out light, with lower specific gravity, just like in diabetes insipidus. Mind you, though, when normal, "unassisted" body diuresis returns and you haven't replenished lost water yet, your specific gravity will be higher than baseline because you just lost so much water with that diuretic.
c)diabetes
--depends on what diabetes...In insipidus, it's lower (see above), in mellitus, it's higher, because of glucosuria (remember that glucosuria is under normal (without diuretic assistance) metabolic rates, only more glucose coming out.
d)dehydration
--less water in the body--less diluent plus more metabolic wastes from execise--higher specific gravity