The volume V of a gas varies inversely as the pressure P upon it. The volume of a gas is 200 cu cm under a pressure of 32kg/sq. cm

a. find the variation constant

b. what will be its volume under a presure of 40 kg/sq. cm

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- Apr 1st 2008, 08:26 AMimbadatmathword problem
The volume V of a gas varies inversely as the pressure P upon it. The volume of a gas is 200 cu cm under a pressure of 32kg/sq. cm

a. find the variation constant

b. what will be its volume under a presure of 40 kg/sq. cm - Apr 1st 2008, 08:54 AMJhevon
- Apr 1st 2008, 09:17 AMimbadatmath
im sorry that made no sense to me lol i am so lost

- Apr 1st 2008, 09:23 AMjanvdl
I think Jhevon should have wrote it as:

$\displaystyle V = \frac{k}{P}$

Where $\displaystyle V$ is the volume and $\displaystyle P$ the pressure.

In the first question, to find the constant $\displaystyle k$ you need to put the given values for $\displaystyle V$ and $\displaystyle P$ in the equation, and solve for $\displaystyle k$.

In the second question you now make use of that value for $\displaystyle k$ when solving for the volume, $\displaystyle V$. - Apr 1st 2008, 09:40 AMJhevon
- Apr 1st 2008, 12:27 PMimbadatmath
i am confused how to solve for k

- Apr 1st 2008, 12:55 PMTing
As janvdl said, substitute in the given values of V and P and solve for k.

$\displaystyle

200 = \frac{k}{32}

$

Solve for k, multiply both sides by 32. - Apr 1st 2008, 01:31 PMimbadatmath
32*200=6400 is that the value of k

- Apr 1st 2008, 01:33 PMjanvdl
- Apr 1st 2008, 01:39 PMTing
Yes so you have the proportionality formula:

$\displaystyle

V = \frac{6400}{P}

$

To find V when P = 40, substutute P = 40 into the formula. - Apr 1st 2008, 02:16 PMimbadatmath
so the volume in the second one owuld equal 160