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Specialty Chemistry Forums => Other Sciences Question Forum => Topic started by: everydaygame on November 11, 2008, 07:00:36 AM

Title: unit conversion proof?
Post by: everydaygame on November 11, 2008, 07:00:36 AM
Hi, im trying to prove pC/N (coloumb per newton) is equivilant to pM/V (meter per volt) but im stuck

C (coloumb) = F.V (farad by volt)

F (farad) = S4. A2. M-2. Kg-1 

So using F

C= V. S4. A2. M-2. Kg-1


Overall: C/N

N (newton) = Kg. M. S-2

therefore

C/N = V. S4. A2. M-2. Kg-1 / Kg. M. S-2

V. S6. A2 / M3. Kg 2

at this point i cant see how to procced.

What have idone wrong or what realtionship do i need to complete the proof?
Title: Re: unit conversion proof?
Post by: Borek on November 11, 2008, 07:42:41 AM
Explaining your symbols won't hurt. I have no idea what you mean.
Title: Re: unit conversion proof?
Post by: everydaygame on November 11, 2008, 08:41:30 AM
Hi sorry a little presumptive of me, the units are
farads        f
coloumbs    c
Kilograms    kg
meters       m
amperes     a
seconds     s

I really meant to put this in the physical forum i was just browsing the materials section, oh well. Ill leave this here though to avoid a cross post.
Title: Re: unit conversion proof?
Post by: everydaygame on November 11, 2008, 08:47:59 AM
In fact heres the whole thing again:

Hi, im trying to prove pC/N (coloumb per newton) is equivilant to pM/V (meter per volt) but im stuck

C (coloumb) = F x V (farad by volt)

farads        f
coloumbs    c
Kilograms    kg
meters       m
amperes     a
seconds     s
volt           v

F (farad) = S4x A2x M-2x Kg-1

So using F

C= V x S4x A2x M-2x Kg-1


Overall: C/N

N (newton) = Kg x M x S-2

therefore

C/N = V x S4 x A2 x M-2 x Kg-1 / Kg. M x S-2

V x S6 x A2 / M3 x Kg 2

at this point i cant see how to procced.

What have i done wrong or what realtionship do i need to complete the proof?
Title: Re: unit conversion proof?
Post by: Astrokel on November 11, 2008, 09:15:46 AM
hi everydaygame, what is SI base units of Volt? It will be clearer to you once you have express it and so far so good
Title: Re: unit conversion proof?
Post by: Borek on November 11, 2008, 09:21:47 AM
Quote from: everydaygame on November 11, 2008, 08:47:59 AM
farads        f
coloumbs    c
Kilograms    kg
meters       m
amperes     a
seconds     s
volt           v

F (farad) = S4x A2x M-2x Kg-1

Note:
second is s, not S
meter is m, not M
kilogram is kg, not Kg

That's one of the reasons I had no idea what you were writing about.
Title: Re: unit conversion proof?
Post by: everydaygame on November 11, 2008, 09:53:39 AM
thanks for the replies

ahh sorry borek i am aware of the convention i was just being sloppy

I think i may have solved the conversion if some one would check they agree:

Using V = m 2 x kg / s 3 x A

put into

C/N = V x s4 x A2 x m-2 x kg-1 / kg. m x s-2
C/N = A x s 3 / kg x m

as V = m 2 x kg / s 3 x A
    1/ V = A x s 3 / kg x m 2

time both sides by m

    m/v = A x s 3 / kg x m

Title: Re: unit conversion proof?
Post by: Astrokel on November 11, 2008, 10:38:17 AM
That's one possible way and remember to make a concluding statement.
Title: Re: unit conversion proof?
Post by: everydaygame on November 11, 2008, 10:47:14 AM
Thanks just wanted to check it worksnot usre I know what you mean by a concluding statement though
Title: Re: unit conversion proof?
Post by: Astrokel on November 11, 2008, 11:01:19 AM
Conluding statement is something like mathematical induction.

Since C/N = A x s 3 / kg x m  and  m/v = A x s 3 / kg x m as such units of C/N is equalvalent to units of m/V.  (Proved)

Title: Re: unit conversion proof?
Post by: DrCMS on November 11, 2008, 11:07:26 AM
1 Colomb =  1 Joule per volt

1 Joule = 1 Newton metre

C/N = (J/V)/N = ((N.m)/V)/N = m/V