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Thread: 1/2²
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08-01-2011, 09:09 PM #51
Re: 1/2²
surely the whole idea of teaching anyone is to expand their knowledge and understanding. If then one comes at a point where the student is not grasping some explaination because of a fundamental basic. Then the teacher needs to side step and explain that basic issue before moving on.
In this case m/s/s or m/s2. Surely then it is needed to take them off on another learning curve to grasp this little nettle before moving on.
What I don't grasp here is why would you be delivering a level of subject matter to people whom aren't quite up to the level of understanding.
If the've achieved NVQ2 then logically NVQ3 is the next level. The study material will be at a higher level , more in depth. Foundation knowledge should have been achieved at level 2. If understanding of powers etc is not in level 2 then level 3 is where it should be taught surely?
Reality is an elusion created by alcohol deficiency. Quaff and enjoy. [Yorkshire, UK]
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08-01-2011, 09:31 PM #52
Re: 1/2²
Here is part of the Level 3 Rationale...
Cooling Science and Calculations
a) Compare and contrast system performance at a variety of conditions using pressure enthalpy diagrams.
b) Compare and contrast air conditioning processes using the psychrometric chart.
c) Apply equipment and components to cooling applications to allow system selection, design and balancing to be carried out.
d) Describe the effect of heat and vapour transfer to insulated structures.
e) Compare and contrast the use of different refrigerant types in cooling applications.
f) Explain the features and characteristics of zeotropic blends, azeotropes and single fluid refrigerants.
g) Assess heat loads to insulated cooled applications.
h) Describe Boyles Law Charles' Law and the Combined Gas Equation.
i) Explain Dalton's Law of Partial Pressures.
You can see that while it is only the combined gas law they are expected to understand and not the general gas law, which implies an understanding of enthalpy, they are anyway required to understand heat carriage and enthalpy.
Now, heat is energy, energy is force x distance and force is mass x acceleration so acceleration needs to be understood.
In the study of energy the two early difficulties are acceleration and then distance traveled by an accelerating mass. Thereafter all else in physics is derived from energy equation because without energy nothing at all happens and in fact because mass is energy then without energy nothing exists.Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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08-01-2011, 09:43 PM #53
Re: 1/2²
I agree with coolrunnings.........
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08-01-2011, 09:51 PM #54
Re: 1/2²
Combined gas law I guess is what we used to call the general gas equation p1. V1/ t1 = P2.V2/T2 which was "O" level chemistry / physics stuff. However, I am begining to understand your dilema here. As I'm aware too full well that the level of school leaving knowledge for science GCSe doesn't seem to be anywhere as near as the older "O" level papers for Chemistry, Physics and biology.
Even so, if that's a sign of the times there's nothing to be done other than train the students in a manner to which they need in order to get them to the level they need. I was lead to believe NVQ3 is suposed to be equivalent level to "A" level or National certificate (ONC) If the students don't understand basic math such as m/s2 etc at this level they shouldn't be on the course surely.
There is no hope for the future.Reality is an elusion created by alcohol deficiency. Quaff and enjoy. [Yorkshire, UK]
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08-01-2011, 10:05 PM #55
Re: 1/2²
And i agree with Goober,,
Remember we are here for a good time, not a long time.
Trust me i'm a Fridgy.
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08-01-2011, 10:10 PM #56
Re: 1/2²
I to understand, but how it is explained becomes of importance.
Acceleration; what is it?
if you have a body,mass or material that at apoint of time is travelling at a speed and at another point in time is travelling at a faster speed then it has accelerated. Note; "speed is also called velocity"
We firstly have to determine what speed is. Speed is how much distance has been travel in a pre set time, for example 5m/s, this means in one second that the mass have travelled 5 meters (Note, speed can be shown in many ways, "miles/hr, ft/sec")
Now that we understand speed, we can look acceleration.
If we have a starting speed for example 10m/s we then measure one second later and the new speed is 11m/s, we can see that the actual speed has changed by 1m/s.
so how do we write this
change in speed= 1m/s
how long did it take to change this speed= 1 second
Therfore is 1meter per second per second = acceleration is 1m/s/s.
Hopefully this shows a method, with useful information to aid understanding, the gramma may be poor, but thats no my fortie!Last edited by mad fridgie; 08-01-2011 at 10:14 PM.
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08-01-2011, 10:18 PM #57
Re: 1/2²
Indeed, that is the combined and then the general is PV = mRT and the universal uses moles instead of mass and because mole for mole the energy per volume.pressure.temperaure is the same for every gas the constant R is the universal whereas for the general the gas constant is specific to that gas because the mass per mole depends on the molecular mass. The universal is then PV = nRT where n is the number of moles. If n or m are one then the formula are:
PV = RT (general gas constant R)
PV = RT (universal gas constant)
PV is energy and RT is energy so PV = RT is basically saying Energy = Energy
Energy is work or tha ability to do work, work is force x distance and force is mass x acceleration.
Standards are dropping right across the western world though more so in some countries than in others.
I meet a lot of techs who have done level 3 but do not feel they still understand PH charts or more importantly psychometrics and many want to understand fans and ducts. This is why I am designing a 2 day physics training course that is purely HVAC&R orientated - no nonsense stuff - nothing excessive - just what is required for a tech to be a good commissioning tech confident with why the ducting or water systems or ahu's are designed the way they are and why they are commissioned the way they are and what room to move do they have when they need to modify systems.Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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08-01-2011, 10:23 PM #58
Re: 1/2²
Moles dig up my garden, so before using "Mole" as terminilogy, should you not first explain how Mole is related to mass.
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08-01-2011, 10:24 PM #59
Re: 1/2²
Yes, it is that the sort of approach that needs to be taken. I will have to scan the articles and email them to you - I don't want to be writing the physics articles on here then publishing them - it wouldn't make sense - so I am just sticking to particular points - at the moment that point is "working with fractions as pertains to elementary physics"
Knowing the difference between speed and velocity is important. For instance the difference between speed and velocity is important in developing an understanding of efficiency.
Velocity/speed is the efficiency factor.Last edited by DTLarca; 08-01-2011 at 10:26 PM.
Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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08-01-2011, 10:34 PM #60
Re: 1/2²
We have to presume that those that we are trying to teach no little, we therefore need to start at the beginning slowly bring up the level of knowledge and understanding, if we move to fast, then all is lost!
The difficulty may be where we lie within the peer group, when you at at your oxford group then yes you should be using every word in the dictionary, but when talking to me, if I have learnt it on the Jeremy Kyle show, then I do not know it!! (bit of humour aids leaning0
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08-01-2011, 10:38 PM #61
Re: 1/2²
Lol, I don't want to be discussing all that yet
Avogadro found that if you had equal volumes of different gases but all the gases were at the same pressure and same temperature then they would have equal numbers of molecules.
He realised that the reason all these identical volumes of gases at the same pressures and temperatures weighed differently was because they each had different molecular masses.
He then decided that if he weighed 2 grams of hydrogen which had atomic mass unit arbitrarily set at 1 he would measure the volume and call that the gram mole. At 0°C and atmospheric pressure 2 grams of hydrogen took up 22.4 litres.
Anyway - you and nevgee are hijacking my thread
I don't want to be getting into all the meat of this stuff here - I want to fine tune the finer principles such as at the moment fractions and physics.Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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08-01-2011, 10:42 PM #62
Re: 1/2²
[quote=DTLarca;216626]
the general is PV = mRT and the universal uses moles instead of mass and because mole for mole the energy per volume.pressure.temperaure is the same for every gas the constant R is the universal whereas for the general the gas constant is specific to that gas because the mass per mole depends on the molecular mass. The universal is then PV = nRT where n is the number of moles. If n or m are one then the formula are:
PV = RT (general gas constant R)
PV = RT (universal gas constant)
Ideal gas equation?Reality is an elusion created by alcohol deficiency. Quaff and enjoy. [Yorkshire, UK]
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08-01-2011, 10:44 PM #63
Re: 1/2²
Ok I'll back off .....
Reality is an elusion created by alcohol deficiency. Quaff and enjoy. [Yorkshire, UK]
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08-01-2011, 10:52 PM #64
Re: 1/2²
Boyles, Charles and then the derived combined then general equations assume ideal gases.
This is why PH charts are preferred to equations for vapour compression calcs because vapours have molecules that do not behave entirely independent of each other - nearer the saturation zone, as is the case even with compressor discharge gases, there is friction between the molecules and so the powers involved in processing vapours are higher than those calculated for ideal gases.Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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08-01-2011, 11:35 PM #65
Re: 1/2²
Mad Fridgie,,,what's a Mole?
Remember we are here for a good time, not a long time.
Trust me i'm a Fridgy.
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08-01-2011, 11:47 PM #66
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09-01-2011, 12:02 AM #67
Re: 1/2²
Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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09-01-2011, 12:21 AM #68
Re: 1/2²
Mad Fridgie,
Thought so, it's the same here.Remember we are here for a good time, not a long time.
Trust me i'm a Fridgy.
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09-01-2011, 01:25 AM #69
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09-01-2011, 01:39 AM #70
Re: 1/2²
Frank said 1/2/1/2 = 1/2/2 = 0.25
But 1 half divided by 1 half is 1.
1/2/1/2 is the same as 1/2 divided by 1/2 = 1 because 1/2 goes into 1/2 just once and precisely just once.
Frank no doubt took one look at this and thought "Gawd - what was I thinking".
Instead of harassing me why don't you just have a vote or something - start a pole of sorts. I'm not a democratic person, I admit, I believe all opinions should be supported by solid argument and evidence rather than merely by popularity but what the hell - do the democratic thing anyway and set up a vote for your grief.Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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09-01-2011, 01:48 AM #71
Re: 1/2²
1/2/1/2=.25
broken down in sequence
1/2 = .5
.5/1=.5
.5/2= .25
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09-01-2011, 01:52 AM #72
Re: 1/2²
Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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09-01-2011, 01:53 AM #73
Re: 1/2²
I agree with Slingblade...........
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09-01-2011, 02:02 AM #74
Re: 1/2²
Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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09-01-2011, 02:34 AM #75
Re: 1/2²
Here we go, scroll down to complex fractions and have a quick read...
http://en.wikipedia.org/wiki/Fraction_(mathematics)
I'm going to print that link off and read it tomorrowOnly the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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09-01-2011, 07:55 AM #76
Re: 1/2²
Speed is the magnitude of velocity. Velocity has both magnitude & direction - it is a vector quantity.
http://en.wikipedia.org/wiki/SpeedLast edited by desA; 09-01-2011 at 07:58 AM.
Engineering Specialist - Cuprobraze, Nocolok, CD Technology
Rarefied Technologies ( SE Asia )
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09-01-2011, 08:17 AM #77
Re: 1/2²
What I was trying to show, is how training should be built,
What is magnitude and what is a vector quantity?
We are looking at training techs, so theorectical excellence has to be tempered with practrical realism, (with time more greater levels of theorectical)
So going back to speed and velocity, each is shown in the same method M/S, KM/Hr, etc, so practically is the same.
The nature of engineering is that it always leads to further questions and increase requirement of knowledge
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09-01-2011, 08:33 AM #78
Re: 1/2²
Begin with Newton's Laws of motion, then build up all the required components. It is all fairly straightforward - high-school maths.
Bringing in this highly-unconventional continued fraction approach will, I fear, only lead to more confusion.Engineering Specialist - Cuprobraze, Nocolok, CD Technology
Rarefied Technologies ( SE Asia )
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09-01-2011, 08:45 AM #79
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09-01-2011, 08:49 AM #80
Re: 1/2²
http://en.wikipedia.org/wiki/Newton's_laws_of_motion
There we go.Engineering Specialist - Cuprobraze, Nocolok, CD Technology
Rarefied Technologies ( SE Asia )
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09-01-2011, 09:02 AM #81
Re: 1/2²
http://en.wikipedia.org/wiki/Dimensional_analysis
This may also be helpful, Marc.Engineering Specialist - Cuprobraze, Nocolok, CD Technology
Rarefied Technologies ( SE Asia )
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09-01-2011, 05:05 PM #82
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09-01-2011, 05:13 PM #83
Re: 1/2²
Exactly as I saw the equation.
Frank said 1/2/1/2 = 1/2/2 = 0.25
But 1 half divided by 1 half is 1.
1/2/1/2 is the same as 1/2 divided by 1/2 = 1 because 1/2 goes into 1/2 just once and precisely just once.
Frank no doubt took one look at this and thought "Gawd - what was I thinking".
If it was written (1/2)/(1/2) then I would have looked at it differently. There are obviously limitations to the way formula's can be written in the forum
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09-01-2011, 05:25 PM #84
Re: 1/2²
If we were to say it is permissible to call the question ambiguous then we would have to give all possible answers as for something to be ambiguous there has to be two or more possible answers - not just one - if only one answer is given then the question was not perceived as ambiguous but was merely misunderstood.
If the question has more than one possible answer then they might include those derived from interpretations such as...
1/(2/(1/2)) = 0.25
1/((2/1)/2) = 1
But to say that 1/2/1/2 just means 1 divide 2 then divide 1 then divide 2 is to treat 1/2/1/2 as an instruction sequence rather than a fraction. If it is to be treated as a fraction then is has to be broken down into numerators and denominators.
Now, can we have a fraction such as 1/2/2?
No we cannot. A fraction must clearly demarcate numerator from denominator.
The convention, in the absence of brackets, is to start at the top identifying numerator then denominator then numerator then denominator.Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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09-01-2011, 05:44 PM #85
Re: 1/2²
Reality is an elusion created by alcohol deficiency. Quaff and enjoy. [Yorkshire, UK]
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09-01-2011, 05:46 PM #86
Re: 1/2²
Seems like you are going back to your old ways my friend.
Do you ever admit to being wrong, or in fact admit to possibly making an error?
There must be a psycological term for someone that is never wrong..........
Count me out of any further responses.
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09-01-2011, 05:53 PM #87
Re: 1/2²
Indeed
m/s/s when treated with the conventions universally applied to fractions in the western world (perhaps everywhere else too) is interpreted as m/s/s/1 which was the whole reason for me starting the thread because I come across so many people who do not understand this and at the same time I believe this to be one of the key reasons people struggle to make full use fo the tools of physics.
If m/s/s was not implicitly m/s/s/1 then we just could not get to m/s²
m/s/s/1 is the same as m/s x 1/s = m/s²
And if you accept that then you have to accept also that 1/2/1/2 = 1 otherwise you are flat out contradicting yourself.Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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09-01-2011, 06:04 PM #88
Re: 1/2²
Are you taking about me Frank?
Firstly - I have never changed my ways and never will - my ways and me are the same thing - they are inseparable.
When I know I am wrong I out loud announce that I am wrong. But right now I believe I am right about this - I could be wrong - that seems to me to be possible - that is why I started the thread - to weigh up a balance of arguments for and against. But so far I believe the arguments for are very much stronger than the arguments against and so this far I genuinely believe your arguments (not you) to be wrong and my arguments (not me) to be right.
Someone who is never wrong is a genius of extraordinary levels. But if you read David Hume's works you would understand that we can only ever learn from making mistakes. If I know a good amount of stuff then it is because I have more experience than others at being wrong about the same stuff at some stage.
Since you can only learn from being wrong and making mistakes - because being right is probabilistic and never a certainty - I put these questions up so that I and others can become more right out of experiencing more often more mistakes. If you are not willing to make mistakes then you are also not willing to learn.
Do you honestly believe - without doubt - that your answer is the correct one?
Do you know what the definition of arragance is?Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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09-01-2011, 06:08 PM #89
Re: 1/2²
(.)(.)
I think i've found my level
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09-01-2011, 06:09 PM #90
Re: 1/2²
Frank - use this online calculator to calculate 1/2/1/2
http://www.calculatorsoup.com/calcul.../fractions.phpOnly the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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09-01-2011, 06:31 PM #91
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09-01-2011, 06:41 PM #92
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09-01-2011, 06:43 PM #93
Re: 1/2²
^ lol...
Engineering Specialist - Cuprobraze, Nocolok, CD Technology
Rarefied Technologies ( SE Asia )
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09-01-2011, 06:52 PM #94
Re: 1/2²
Tits or tyres, nothing but trouble
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09-01-2011, 06:55 PM #95
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09-01-2011, 07:11 PM #96
Re: 1/2²
Question
If I'm stood underneath two condensing units, one weighing 100kg and one weighing 75kg, each vertically mounted side by side with a space gap of 300mm, at a height of 100 meters, air temperature @ 20 deg C, RH 68.6%, wind speed @ 11.7 mph/19.78 kph. And both units detach themselves equally at the same time due to poor fixings, fall and land on me.
Which unit will hurt me the most?
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10-01-2011, 12:05 AM #97
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10-01-2011, 12:16 AM #98
Re: 1/2²
Chilli, neither as you would be dead, but.. thats just an opinion. Cartoons come to mind,whistle.... followed by splat and a cloud of dust. Coyote lives to recalculate why both condensing units fell at different speeds.
To the optimist, the glass is half full. To the pessimist, the glass is half empty.
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10-01-2011, 08:45 AM #99
Re: 1/2²
So Frank - do you not feel compelled to admit error yet?
Does "Count me out of any further responses" mean "Oh **** - if I hang around here I'm going to have to sooner or later admit I was wrong"?
You know, the difference between an arrogant antagonist and a sincere one is that the arrogant one will merely rebut your claims without explanation whereas a sincere one will at least try offer argument and evidence.
Of course it is possible you genuinely think you are right? I think that would be very odd - it would very much surprise me - but it could still just be that you genuinely believe you are right - in which case you are not obliged to admit you are wrong - it is sheer nonsense to ask someone to admit they are wrong when they feel sure that they are correct.Only the dogmatist says he will never change his mind. We all know that some of our opinions are wrong but none of us know which they are for if we did then they just wouldn't be our opinions. - JS Mill.
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10-01-2011, 09:07 AM #100
Re: 1/2²
I do think it comes down to how it is written, if I remember rightly, if you were calculating a fraction, the fraction was in a small font, with the comand in a larger font 1/2/1/2
The answer would then be clearly 1Last edited by mad fridgie; 10-01-2011 at 09:39 AM.