Nishi-chan Posted February 26, 2011 Report Share Posted February 26, 2011 Ugh, just reading Dark's question gave me a headache. I am so writing it down and taking it to my Math and Science teacher on Monday. My question: does salt lower or increase the freezing point of water? Link to comment Share on other sites More sharing options...
seattleite Posted February 28, 2011 Author Report Share Posted February 28, 2011 Salt lowers the freezing point. Link to comment Share on other sites More sharing options...
Dark Posted February 28, 2011 Report Share Posted February 28, 2011 A good way to think about it is that the oceans rarely freeze, even when sea temperatures get below 20 degrees F. Because the salt content of oceans is relatively high, the freezing point of the water is greatly reduced. I completely forgot chemically why this happens, but I think it has to do with the balance of water molecules with salt compounds. Link to comment Share on other sites More sharing options...
Nishi-chan Posted February 28, 2011 Report Share Posted February 28, 2011 So has anyone solved your equation, math, sphere, thingy yet Dark? Link to comment Share on other sites More sharing options...
Dark Posted March 1, 2011 Report Share Posted March 1, 2011 No. <___< That was the reason I got a 94 on my quiz as opposed to a 99. And I still don't know how to do it, so I better learn before the final. Link to comment Share on other sites More sharing options...
Nishi-chan Posted March 2, 2011 Report Share Posted March 2, 2011 Wait, that was a question on a test you took?! What level math are you in?? Link to comment Share on other sites More sharing options...
Dark Posted March 2, 2011 Report Share Posted March 2, 2011 Calc II. I think I already made that clear. Wasn't someone going to ask their math teacher about that? Please do; I'm too lazy to ask mine (not to mention I never remember to). Link to comment Share on other sites More sharing options...
Nishi-chan Posted March 2, 2011 Report Share Posted March 2, 2011 I'll do it. He only teaches Geometry and Calc I though. -writes the question down- Link to comment Share on other sites More sharing options...
42.42.564 Posted March 2, 2011 Report Share Posted March 2, 2011 integral(from 0 to 5) of (5-x)*(4/3)pi*(x^3) dx maybe. name: 42.42.564 expertise: good at nothing.. Link to comment Share on other sites More sharing options...
Nishi-chan Posted March 3, 2011 Report Share Posted March 3, 2011 [center][spoiler=Dark's question]Imagine a sphere with radius 5 meters. At any given point on the sphere, the density is (5 - x) kilograms per meter cubed, where x is the distance from the center. This means at the center, the density is 5 kg/m^3, and all around the outside, the density is 0. Now, find the mass of the sphere in kilograms.[/spoiler] [spoiler=My first attempt](The formula for finding the mass of a sphere is 4/3πr^3d) 4/3 x π x 5^3 x 5 kg/m^3 (5^3 = 125) 4/3 x π x 125 x 5 kg/m^3 (4/3 x 125 = 166.66...) 166.66... x π x 5 kg/m^3 (round 166.66... to 167 for approximation) (167 x 5 = 840) Mass = 840π kg/m^3 (left in pi form) 2,637.6 kg/m^3 (approximated)[/spoiler] [spoiler=Second attempt(double checking)]I did everything the same but instead of rounding 166.66... I made it into a fraction, and got this answer; 2,617.993878 I don't know which one is right, I checked with my science teacher who taught Calc once, and my math teacher. They triple checked my work and found no errors.[/spoiler] Dark you bastard.[/center] Link to comment Share on other sites More sharing options...
Dark Posted March 3, 2011 Report Share Posted March 3, 2011 It kind of needs to be exact. I could have estimated it myself. [quote name='42.42.564' timestamp='1299085770' post='5045866'] integral(from 0 to 5) of (5-x)*(4/3)pi*(x^3) dx maybe. name: 42.42.564 expertise: good at nothing.. [/quote] That doesn't really take into account the density at each point. Link to comment Share on other sites More sharing options...
42.42.564 Posted March 3, 2011 Report Share Posted March 3, 2011 is 5-x the density at a given point? Link to comment Share on other sites More sharing options...
Dark Posted March 3, 2011 Report Share Posted March 3, 2011 Oh, my bad, I read that incorrectly. So integrate from 0 to 5 of density (at radius r) times sphere with radius r. Yeah, I think that makes a lot of sense. I'll double-check with my math teacher if I ever remember. Link to comment Share on other sites More sharing options...
42.42.564 Posted March 3, 2011 Report Share Posted March 3, 2011 one clarification would be nice: At any given point on the sphere, the density [b](Of the hallow sphere the point is on, or just the point?) [/b] is (5 - x) kilograms per meter cubed, where x is the distance from the center I think the set up would be entirely different if it is actually the density of a "point" Link to comment Share on other sites More sharing options...
Dark Posted March 3, 2011 Report Share Posted March 3, 2011 Of the entire sphere. You are basically adding spheres from radius 0 to radius 5, each sphere having an increasingly lower density. When I say point, I am referring to any point that lies on the sphere with a certain density inside of the radius 5 sphere. Link to comment Share on other sites More sharing options...
42.42.564 Posted March 3, 2011 Report Share Posted March 3, 2011 cal 2, it can't be this simple >.<, there has to be some triple integral with theta phi radius .. i am having this feeling >.> Link to comment Share on other sites More sharing options...
Dark Posted March 4, 2011 Report Share Posted March 4, 2011 I'm pretty sure it is that simple. First semester was just Calc I review and a few new concepts, but second semester isn't too much fun. I'll get through it, though. Ask me more chem questions; I've been tutoring some sophmores and juniors taking chem, so it has been a real refresher of s[b][/b]hit I did two years ago. but physics is moar fun Link to comment Share on other sites More sharing options...
Nishi-chan Posted March 4, 2011 Report Share Posted March 4, 2011 All the physics classes at my school went to Knott's Berry Farm today. Lucky bastards. Link to comment Share on other sites More sharing options...
Dark Posted March 4, 2011 Report Share Posted March 4, 2011 You live in California. All I remember about that amusement is park is that I went with my cousins, and there was a coaster called Ghost Rider that killed my neck. Link to comment Share on other sites More sharing options...
Nishi-chan Posted March 4, 2011 Report Share Posted March 4, 2011 How the hell do you know where I live? Link to comment Share on other sites More sharing options...
Dark Posted March 4, 2011 Report Share Posted March 4, 2011 [quote name='Niashi Inumaki' timestamp='1299199199' post='5049359'] How the hell do you know where I live? [/quote] Wow. <___< Because Knott's Berry Farm is in California, maybe? HERP-DE-DERP Link to comment Share on other sites More sharing options...
Nishi-chan Posted March 4, 2011 Report Share Posted March 4, 2011 Didn't know there was only one >_< Don't judge meh! Link to comment Share on other sites More sharing options...
Cody Frost Posted March 23, 2011 Report Share Posted March 23, 2011 Name: Wolfy Eddy (AKA Eddy) Areas of Expertise at: College level: *Math up to College AB Calculus (still studying BC part but I can still do a few questions on this section) *Biology *Physical Geography *Environmental Science *American Government Some Psychology Some ENGL Composition High School Level: *Economics Some Chemistry Some Integrated Physics and Chemistry Currently learning: Italian (beginners-intermediate; I might need help in this ) Told ya I was studying....so 2012 will probably hit Link to comment Share on other sites More sharing options...
Î’yakuya Posted April 4, 2011 Report Share Posted April 4, 2011 * Name: Byakuya Kuchiki * Areas of Expertise (What subject(s) are you good at?) Science, in the fields of Health, Psychology, and a little Astronomy, Geometry, Also a US history expert, kinda. etc. - Experience ( Optional, goes with Areas of Expertise, High School Education, College, Level of Math/Science etc. Include if Areas of Expertise doesn't explain well enough.) Been having good grades around A's or B's on these grades. Most expertise comes from reading lots of books. Link to comment Share on other sites More sharing options...
~The Dark one~ Posted April 4, 2011 Report Share Posted April 4, 2011 [font="tahoma, arial, verdana, sans-serif"]* Name Pokefantic[/font] [font="tahoma, arial, verdana, sans-serif"]* Areas of Expertise (What subject(s) are you good at?) math science Spanish [/font] [font="tahoma, arial, verdana, sans-serif"]algebra some trig probability geometry [/font] Link to comment Share on other sites More sharing options...
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