Ohms law

[martinh89]

Cab somebody pleas help, im perfectly ok with ohms law until squared and square roots are brought in
Could sombody please explain to me why and how i do this equation.

P=v2/r and the question is make v2 the subject instead of p

 

[telectrix]

you do it by transposing the formula. it's so easy if you remember a simple clue. in your example, yo want to get Vsq. on it's own. right. so. because an equation is, by definition, the same on both sides of the =, then whatever yo do to both sides, retains the equation.#so multiply each side by r. left side becomes P x r, right side becomes (Vsq.x r) /r . cancel the r's on theright and you're left with .... Pr = Vsq.

 

[Marvo]

Are you a trainee or currently on a training course?

If you want V² to be the subject then multiple both sides of the formula by R.

*EDIT* Tel beat me to it.

 

[telectrix]

i went to all that long-winded explanation just to have you put it simply. bloody grass skirt warriors. LOL.

 

[Hawkmoon]

Also if you want V...

V2 = PR is the same as

V = square root (PR)

Anything you move in a formula (to the other side of the =) changes its designation so:

square becomes square root.
Items above the line on one side move to below the line on the other (and vice versa).

So if you have a problem with maths (particularly with more complex equations) you can use this rule to manipulate the formula and leave your subject on its own (and above the line).

In your example the R (which is below the line) is simply moved to the other side of = and placed above the line (next to P) leaving you with V2 on its own.

P = V2
xxxxR

becomes...

PR = V2


If your required subject is R then you first move R to other side of = to ensure it is above line then move the P so the R is on its own...

R = V2
xxxx P

This method stands good for most formula you come up against in theory to level 3 - and you don't need to worry about multiplying both sides with anything.

 

[Badged01]

And there was me thinking all the maths to do with calculations was easy. All of a sudden Ive now got to rememember 3 equations ..... do i divide it, subtract it, multiply it or root it? The equation that is ..... :redface:

 

[martinh89]

Also if you want V...

V2 = PR is the same as

V = square root (PR)

Anything you move in a formula (to the other side of the =) changes its designation so:

square becomes square root.
Items above the line on one side move to below the line on the other (and vice versa).

So if you have a problem with maths (particularly with more complex equations) you can use this rule to manipulate the formula and leave your subject on its own (and above the line).

In your example the R (which is below the line) is simply moved to the other side of = and placed above the line (next to P) leaving you with V2 on its own.

P = V2
xxxxR

becomes...

PR = V2


If your required subject is R then you first move R to other side of = to ensure it is above line then move the P so the R is on its own...

R = V2
xxxx P

This method stands good for most formula you come up against in theory to level 3 - and you don't need to worry about multiplying both sides with anything.

Very helpful thankyou
I don't struggle with maths Im just struggling to see the pattern , but your method is very helpful ive tried it with a few different outcomes and its working for