Physics question

**SMOKEU** · 13th August 2010, 21:32

I'm stuck on a question that I have to do for uni. I have a formula I have to work with which goes like this: p2 = p1 X v1 / v2

I need to make v2 the subject, as in v2 = ?

Any help with this would be appreciated.

**neels** · 13th August 2010, 21:39

can anyone remeber how that bedmas thing goes, it's either...

P2=P1xV1/V2

=> V2xP2=P1xV1

=> V2=P1xV1/P2

or

P2=P1xV1/V2

=> P2/P1=V1/V2

=> (P2/P1)/V1 = V2

**Laava** · 13th August 2010, 21:49

B1 + B2 = ?...........

**SMOKEU** · 13th August 2010, 21:55

Originally Posted by Laava

B1 + B2 = ?...........

............does it equal BJ?

**Cloggy** · 13th August 2010, 22:23

Originally Posted by SMOKEU

I'm stuck on a question that I have to do for uni. I have a formula I have to work with which goes like this: p2 = p1 X v1 / v2

I need to make v2 the subject, as in v2 = ?

Any help with this would be appreciated.

If I remember correctly when you move an element to the other side of the = sign it reverses. So division become multiplication etc.
p2 x v2 = p1 x v1
v2 = (p1 x v1) / p2
Don't quote me on this though. Been a long time since I did this stuff.

Edit: Just double checked with substituting simple numbers into the equation and this is correct.

**Ntoxcated** · 13th August 2010, 23:06

If A = B / C then B = A x C and C = B / A

So, if p2 = p1 x v1 / v2 then v2 = p1 x v1 / p2

Checked by plugging in some some numbers.

6 = 3 x 4 / 2 so 2 = 3 x 4 / 6

**Marmoot** · 13th August 2010, 23:50

Originally Posted by Cloggy

If I remember correctly when you move an element to the other side of the = sign it reverses. So division become multiplication etc.
p2 x v2 = p1 x v1
v2 = (p1 x v1) / p2
Don't quote me on this though. Been a long time since I did this stuff.

Edit: Just double checked with substituting simple numbers into the equation and this is correct.

You are correct.

Multiplication to division, and vice versa.
If A xB = C
then A = C /B
OR
If A /B = C
then A = C xB

Addition to substraction, and vice versa.
If A +B = C
then A = C -B
OR
If A -B = C
then A = C +B

Same goes with :
- Square and Sq.Root
- Integral and diferential

**DMNTD:Me** · 14th August 2010, 05:14

Originally Posted by SMOKEU

I need to make v2 the subject, as in v2 = ?

Right then...arguably V2's make the bestest sound out of all motor configurations.

**Jantar** · 14th August 2010, 06:35

Originally Posted by SMOKEU

I'm stuck on a question that I have to do for uni. ....

Uni? That is 3rd form level algebra.

P2 = P1 X V1/V2
Multiply both sides by V2
P2V2 = P1V1
Divide both sides by P2
V2 = (P1/P2) X V1

**Grasshopperus** · 14th August 2010, 09:53

Yeah, that's 3rd form algebra

Check this link out; it's from the Khan Academy which host an unbelievable number of free online tutorials for most science and math related subjects. It's very good.

http://www.khanacademy.org/video/alg...ar-equations-4

**Edbear** · 14th August 2010, 15:33

If the form fits...

**slofox** · 14th August 2010, 16:32

Originally Posted by Cloggy

If I remember correctly when you move an element to the other side of the = sign it reverses. So division become multiplication etc.
p2 x v2 = p1 x v1
v2 = (p1 x v1) / p2
Don't quote me on this though. Been a long time since I did this stuff.

Edit: Just double checked with substituting simple numbers into the equation and this is correct.

Correct...

**pzkpfw** · 14th August 2010, 16:51

Originally Posted by SMOKEU

Sounds complicated.

1234567890

**Oakie** · 14th August 2010, 17:00

I was fine with maths until they started putting the alphabet in it. Never got it.
Oh, and in in the 33 years since I left school I've never needed it. (just as well).