NSFCD

Generally Speaking => Power On => Topic started by: Sabby on September 29, 2007, 12:43:49 PM

Title: homework help
Post by: Sabby on September 29, 2007, 12:43:49 PM
alot of the people here are older than me so this question should be easy, and since there is no board for this, i will ask here. this is science and it involves boyle's law.i already know how to set up the formula witch in my question would be "P2=(22.5 kPa)(155 cm cubed)divided by 90 cm cubed" and P stands for pressure. it wants me to solve for P2. ??? ???
Title: Re: homework help
Post by: えっちーせんぱい on September 29, 2007, 12:47:12 PM
What the hell is that?
Title: Re: homework help
Post by: Sabby on September 29, 2007, 12:50:02 PM
it a stupid science question, i hate formulas. :(
Title: Re: homework help
Post by: Silverhawk79 on September 29, 2007, 12:51:48 PM
Eh...too bad I got a C+ in Chemistry. >_>
Title: Re: homework help
Post by: Sabby on September 29, 2007, 12:55:32 PM
here is a better layout
       (22.5 kPa)(155 cm cubed)
P2=-----------------------------------
                  90 cm cubed
Title: Re: homework help
Post by: Doodle on September 29, 2007, 01:07:15 PM
Ummm... I have no clue...  ???
Title: Re: homework help
Post by: phatyo on September 29, 2007, 01:08:40 PM
The anwer is p=42 your done
Title: Re: homework help
Post by: Doodle on September 29, 2007, 01:09:52 PM
Quote from: phatyo on September 29, 2007, 01:08:40 PM
The anwer is p=42 your done

Did you ACTUALLY do that!?
Title: Re: homework help
Post by: Sabby on September 29, 2007, 01:11:37 PM
how the heck did you do that? ???
Title: Re: homework help
Post by: Sabby on September 29, 2007, 01:12:14 PM
i need more help with HOW to do it, because i have more questions like it.
Title: Re: homework help
Post by: phatyo on September 29, 2007, 01:14:22 PM
Quote from: SBSTN1 on September 29, 2007, 01:12:14 PM
i need more help with HOW to do it, because i have more questions like it.
On the old Nsider there was a home work help team :/ some one needs to come up with the same thing here!
Title: Re: homework help
Post by: Sabby on September 29, 2007, 01:16:56 PM
actually that would have to be wrong. if volume 2 is less than volume 1, wouldn't pressure 2 be less than pressure 1?(pressure 1 is 22.5 kPa)
Title: Re: homework help
Post by: Silverhawk79 on September 29, 2007, 01:17:11 PM
Don't you just have to multiply the top two numbers, and then divide by the bottom? >_>
Title: Re: homework help
Post by: Sabby on September 29, 2007, 01:19:12 PM
Quote from: Silverhawk79 on September 29, 2007, 01:17:11 PM
Don't you just have to multiply the top two numbers, and then divide by the bottom? >_>
that is the first thing i though, but then i thought that would be multiplying the pressure into the volume, and it seems weird to do that.
Title: Re: homework help
Post by: Omega Pirate on September 29, 2007, 01:27:54 PM
Boyle's Law:
P1 * V1 = P2 * V2


P1 = 22.5kPa
V1 = 155 cm^3

P2 = ?
V2 = 90cm^3


So.....we plug in the values:

22.5 * 155 = P * 90

=

3,487.5 = P * 90


Solve for P by dividing 3,487.5 by 90, and: 38.75kPa.


Gas laws are actually very simple. Just plug in the values you have, and then just do the basic algebra to finish it off. I never got it at first either, but trust me, once you do get it, you will feel really dumb for not getting it sooner. I sure as heck did.
Title: Re: homework help
Post by: Sabby on September 29, 2007, 01:32:38 PM
thank you very much, i am in home school so i don't have very many options when i do get confused with a question.