College/University Homework Help Thread v2.0

2011-11-27 10:58:07

#51

Jay: Bork! Bork! Bork!; +2,006|5573|London, England

Ryan wrote:
And I don't find it difficult. I'm probably sitting at an 80 or an 85 in the class, but when it comes to the labs, nothing seems to ever work out the way it should.

And yea, I plan on working for an oil company, probing underground for reservoirs and such. But there is alot more you can do with a geophysics major as well, but working for an oil company seems the most probable. Up in northern Alberta, oil is huge up there.

Well, you are certainly in the right part of the world for the work There was a time when I wanted to study geology too. One of my army buddies used to tell stories of his prior life as a roughneck and he was always jealous of the geologists that would sit in their trailer for weeks on end doing nothing aside from testing the samples left on their doorstep and staving off boredom. Seemed like a super easy paycheck to me

"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat

2011-11-27 10:58:38

#52

Ryan: Member; +1,230|7058|Alberta, Canada

Organic chem looks like death, from what I've seen my friends go through lol.

I wanted to do atsrophysics, or astronomy, but the career base is so limited.

2011-11-27 11:00:51

#53

Jay: Bork! Bork! Bork!; +2,006|5573|London, England

Ryan wrote:
Organic chem looks like death, from what I've seen my friends go through lol.

I wanted to do atsrophysics, or astronomy, but the career base is so limited.

Pretty much professor or nothing in those fields. I got really lucky with my physics professor; dorky (but funny) Indian astrophysicist that had done a lot of work on MRI machines. Half of the problems he gave us had to do with circular orbits of planets and the like. Completely useless, but fun

"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat

2011-11-27 11:10:45

#54

Ryan: Member; +1,230|7058|Alberta, Canada

Jay wrote:
Ryan wrote:
Organic chem looks like death, from what I've seen my friends go through lol.

I wanted to do atsrophysics, or astronomy, but the career base is so limited.
Pretty much professor or nothing in those fields. I got really lucky with my physics professor; dorky (but funny) Indian astrophysicist that had done a lot of work on MRI machines. Half of the problems he gave us had to do with circular orbits of planets and the like. Completely useless, but fun

My physics teacher seems to put an escape velocity question on every quiz, whether it's relevant or not. I just put the formula on the forumla sheet, plug in the numbers, and get an easy 4 marks. Haha.

But yea, I didn't wanna be a professor.

2011-11-27 11:16:38

#55

Jay: Bork! Bork! Bork!; +2,006|5573|London, England

Ryan wrote:
Jay wrote:
Ryan wrote:
Organic chem looks like death, from what I've seen my friends go through lol.

I wanted to do atsrophysics, or astronomy, but the career base is so limited.
Pretty much professor or nothing in those fields. I got really lucky with my physics professor; dorky (but funny) Indian astrophysicist that had done a lot of work on MRI machines. Half of the problems he gave us had to do with circular orbits of planets and the like. Completely useless, but fun
My physics teacher seems to put an escape velocity question on every quiz, whether it's relevant or not. I just put the formula on the forumla sheet, plug in the numbers, and get an easy 4 marks. Haha.

But yea, I didn't wanna be a professor.

Have fun with it man. I had a lot of classes that I enjoyed throughly and some, like multivariable calculus, that made me want to slit my wrists. Out of the Newtonian physics semester you're taking, I enjoyed thermo the most.

"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat

2011-11-28 09:29:32

#56

Jebus: Looking for my Scooper; +218|5979|Belgium

I need excel help

So I'm making a financial plan for a dietitian, but I'm having some problems with the revenue.
On average, a client will come 4 times. Three times in the first three weeks, then two weeks without an appointment and finally a fourth meeting in the next week.

So that makes 4 meetings in 6 weeks (first is one hour, the others are each half an hour long).
Now you see, this gives a problem in november/december.

The new clients in those months will have meetings in year X1 and X2, giving revenue to each of those years. I'm having trouble making this clear in excel, any input?

2011-11-28 09:49:05

#57

Jay: Bork! Bork! Bork!; +2,006|5573|London, England

Rather difficult to help you without seeing the file...

"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat

2011-11-28 10:01:46

#58

Jebus: Looking for my Scooper; +218|5979|Belgium

Jay wrote:
Rather difficult to help you without seeing the file...

I hope this makes my time schedule clear.

http://www64.zippyshare.com/v/3107753/file.html
(one 0.5u (=0.5 hours) went missing in week 52, 6th column)

As you can see, there are a few clients that start in week 52 (and a few weeks before that) that run over into the next year, thus accounting to that year's revenue.

My file however only roughly scetches this situation..

Last edited by Jebus (2011-11-28 10:03:48)

2011-11-28 10:16:07

#59

Jay: Bork! Bork! Bork!; +2,006|5573|London, England

Like this?

https://static.bf2s.com/files/user/51395/Screen%20Shot%202011-11-28%20at%201.14.58%20PM.png

"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat

2011-11-28 10:27:39

#60

Jebus: Looking for my Scooper; +218|5979|Belgium

Yeah bro, I can work with that..

I've tried calculating the hours/week but it keeps messing up with the word.. I've tried 'ignoring' the text by using this formula
=IF(ISNUMBER(C3),C3,"") but it keeps messing up. Could you be so kind to upload your file? I think I can work from there on then

Edit; I think I got the formula working now.. but I don't believe my way is the most efficient way to calculate the hours per week.
edit2: nvm, autosum does it fine lol.

Last edited by Jebus (2011-11-28 10:30:50)

2011-11-28 10:36:10

#61

Jay: Bork! Bork! Bork!; +2,006|5573|London, England

http://www.gamefront.com/files/21035552/time_xls

"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat

2011-11-28 11:01:20

#62

Jebus: Looking for my Scooper; +218|5979|Belgium

Thanks a lot bro, that helps heaps!

2011-11-30 13:14:42

#63

presidentsheep: Back to the Fuhrer; +208|6176|Places 'n such

This is not right:

http://static.bf2s.com/files/user/32093/Untitled.png

edit: they were steel ball bearings, so the density should actually be nearer 8000kg/m^3 but the micrometer I was using wasn't calibrated right. That'll be going in the analysis.

The parts that aren't right are the errors on the densities, the density for the 1.5mm one i've fixed.

edit2: the formula I'm using to calculate my error is Density * sqrt( (error on mass/mass)^2 + (error on volume/volume)^2) )

Last edited by presidentsheep (2011-11-30 13:28:33)

I'd type my pc specs out all fancy again but teh mods would remove it. Again.

2011-11-30 15:31:56

#64

Ryan: Member; +1,230|7058|Alberta, Canada

Quick question:

As far as molality goes, does the mass of the solvent always have to equal 1 kilogram?

Like say I have 5 mol of solute and 250g of solvent (and the solvent is water). Would the molality be 5mol/.250kg? Or do I have to multiply the 250g up so that it becomes 1kg, and then do the same to the solute? So in this case, 5 mol per 250g, so 20 mol per 1000g.

I always get this stuff confused.

Also, what if the solvent isn't water and I'm not given it's density. Say, I have 150mL of benzene as my solvent. I can't just say that's equal to 150g of benzene, right?

2011-11-30 16:03:14

#65

HaiBai: Your thoughts, insights, and musings on this matter intrigue me; +304|5698|Bolingbrook, Illinois

molarity = moles / liters
1g = 1mL
250g = 250mL
250mL = .25L
molarity = 5 moles / .25 liters = 20 mol/L

mass = density x volume
mass = density of benzene x volume
mass = 0.874 g/cm^3 x 150mL
mass = 131 g

2011-11-30 16:15:43

#66

Ryan: Member; +1,230|7058|Alberta, Canada

HaiBai wrote:
molarity = moles / liters
1g = 1mL
250g = 250mL
250mL = .25L
molarity = 5 moles / .25 liters = 20 mol/L

mass = density x volume
mass = density of benzene x volume
mass = 0.874 g/cm^3 x 150mL
mass = 131 g

And if I don't have the density of benzene?

Oh and I'm talking molality not molarity.

Last edited by Ryan (2011-11-30 16:16:07)

2011-11-30 16:17:55

#67

Uzique: dasein.; +2,865|6685

how bout some of that morality

_{libertarian benefit collector - anti-academic super-intellectual}. _{http://mixlr.com/the-little-phrase/}

2011-11-30 16:21:41

#68

HaiBai: Your thoughts, insights, and musings on this matter intrigue me; +304|5698|Bolingbrook, Illinois

Ryan wrote:
HaiBai wrote:
molarity = moles / liters
1g = 1mL
250g = 250mL
250mL = .25L
molarity = 5 moles / .25 liters = 20 mol/L

mass = density x volume
mass = density of benzene x volume
mass = 0.874 g/cm^3 x 150mL
mass = 131 g
And if I don't have the density of benzene?

Oh and I'm talking molality not molarity.

oh oops, misread. i was wondering why a kid near the end of the semester of chemistry was asking about molarity hahah...

and you have to know the density to calculate mass, or at least some other type of information

2011-11-30 16:23:10

#69

Ryan: Member; +1,230|7058|Alberta, Canada

HaiBai wrote:
Ryan wrote:
HaiBai wrote:
molarity = moles / liters
1g = 1mL
250g = 250mL
250mL = .25L
molarity = 5 moles / .25 liters = 20 mol/L

mass = density x volume
mass = density of benzene x volume
mass = 0.874 g/cm^3 x 150mL
mass = 131 g
And if I don't have the density of benzene?

Oh and I'm talking molality not molarity.
oh oops, misread. i was wondering why a kid near the end of the semester of chemistry was asking about molarity hahah...

and you have to know the density to calculate mass, or at least some other type of information

lol, yea, I thought so to, because if I have 150mL of benzene, I need it's density to calculate the mass, from there I can get moles, then from there I can get molality, because m = moles/kg of solvent

So if I don't have density, how do I know the mass of benzene in 150mL? Or is there a different way of solving it?

2011-11-30 16:25:55

#70

HaiBai: Your thoughts, insights, and musings on this matter intrigue me; +304|5698|Bolingbrook, Illinois

if you're literally given a pencil, a piece of paper, and are asked to solve for the mass of 150ml of benzene without being able to use any other type of information, i'm positive it's impossible

2011-11-30 16:28:32

#71

Ryan: Member; +1,230|7058|Alberta, Canada

K so I'm just a retard. I asked the question about benzene as a solvent because it showed up in one of the questions, but I didn't actually have to solve the molality.

All the other questions involve water, or in the ones with benzene, the mass of benzene is given. D'oh.

Thanks though.

2011-12-07 10:35:01

#72

Ryan: Member; +1,230|7058|Alberta, Canada

Quick question:

If I want to differentiate 2^(x^2 - 3x), I usually use the rule that states (a^x)' = a^x * ln(a)

But when I see others differentiate it, it's more like (a^x)' = a^x * ln(a) * x'

So would the derivative of what I stated up there be

2^(x^2 - 3x) * ln(2) * (2x - 3)

Sorry it's hard to read, I hate having to use ^ for powers.

2011-12-07 11:02:38

#73

Jay: Bork! Bork! Bork!; +2,006|5573|London, England

[2ln(2)x -3ln(2)][((1/8)^x)(2^x^2)]

"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat

2011-12-07 11:04:45