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M0BZK
May 19, 2009, 12:48 PM
How do I change P=10nQH to be Q= this one has me completely stumped:mad:



DD

Unknown008
May 19, 2009, 12:50 PM
Your question here is quite difficult to understand...

Is it

P=10nQH

of is there some power?

M0BZK
May 20, 2009, 03:25 AM
Hi Thanks for reply the formula is used in hydro electric systems to work out the power in kw the system will provide. N is the efficiency of the turbine, Q the amount of water in cubic meters per sec and H the head of water. I need to find out the amount of water Q to give a given power output
Hope this is more info for you
Cheers dave

Unknown008
May 20, 2009, 11:36 AM
What I guess is a simple algebra changing the subject of formula:

Q=\frac{P}{10nH}

I don't know if that is the real answer though, for it seems quite simple.. :confused:

M0BZK
May 20, 2009, 12:32 PM
Thanks for that, its is what I thought it should be. This is one area of maths that gets me lost, I just hope that I do not get one in my exam later in the year.

Unknown008
May 20, 2009, 12:36 PM
Oh, that was what you were looking for then!

Let me explain how you come to it:

P=10nQH

Divide everything by 10nH;

\frac{P}{10nH}=\frac{10nQH}{10nH}

You'll see that 10/10 = 1, n/n = 1, H/H= 1;

\frac{P}{10nH}=Q\times1\times1\times1

\frac{P}{10nH}=Q