Math nerds UNITE!

[The Pastor]

Could someone help me out with this please

Im woring out an angle and i get 21.45 (not the real number) then I push the degrees minutes and seconds button and I get 21 degress 20 minnutes 34 seconds (not real numbers)

Which is the corret result?

What happens when you push that button?

Up to now ive just let the angle = 21.45 degress, but now im not sure if that is right.

any help would be awesome.

[Maha]

Time to renew the microwave i think RM.........:lol:

[The_Dover]

one is decimalised you tit.

ie .45 of a degree = 20 minutes and 34 seconds

1 minute = 1/60th of a degree

1 second = 1/60th of a second = 1/3600th of a degree

[ManDownUnder]

one is decimalised you tit.

ie .45 of a degree = 20 minutes and 34 seconds

1 minute = 1/60th of a degree

1 second = 1/60th of a second = 1/3600th of a degree

There are times I just love having you around - that diplomacy, sensitivity and unerring sense of when to back off !!!!

[The Pastor]

So when I work out sine(angle) I should push that button to get the true angle? in school they just leave it?

[The_Dover]

what are you using it for?

I usually just leave a decimal angle. easier to write down and i'm a lazy cunt

[rua]

this is a good site for all sorts of conversions, which shows some workings for reference

http://members.optusnet.com.au/ncrick/converters/main.html

[Maha]

And here i was thinking he was trying to reheat some Chinese......:cool:

[The Pastor]

what are you using it for?

I usually just leave a decimal angle. easier to write down and i'm a lazy cunt

Working out the angle of friction... basiclay tan-1(insert number here) = angle of friction.

So what your saying is, the decimal number is correct but slightly wrong? i.e I wouldnt get marked wrong in an exam?

[judecatmad]

Working out the angle of friction... basiclay tan-1(insert number here) = angle of friction.

So what your saying is, the decimal number is correct but slightly wrong? i.e I wouldnt get marked wrong in an exam?

If it's for an exam, then it all depends on what answer the markers are expecting......'correct' exam answers are not always real-world correct. They are quite often limited by what the curriculum has specified be taught that year and what level is being taught. Was a hard lesson for me to learn that what I was taught at age 15/16 was totally different to age 17/18 then again at Uni! Now I just accept that there's always going to be a next level that I will never understand or be privvy to! LOL (quantum mechanics was my breaking point!!)

If you have been taught to use decimals, then go with that. If you have been taught to work it all out long-hand (which I very much doubt these days) then go with the conversion to degrees/minutes/seconds.

(If it's maths then the decimal is probably all they are after, rounding errors are no great issue. If it were physics then I would expect they would be after the absolute answer)

But then I've not been at school since 1991 and I left Uni in 1997, and both of those were in the UK, so what do I know?! :D

[WarlockNZ]

one is decimalised you tit.

Oh dear god .. i havn't had a laugh like that in ages .. :lol: .. i had no idea about that either .. but the reply was brilliant .. more bling for you, you magnificent bastard. .. ha ha

[The_Dover]

If you want to get full marks just write them both, knob.

[Oakie]

Ahhhh just forget it. I left school 29 years ago (when we had to work those things out without a calculator) and I've never had to use it.

[Oakie thinks for 20 seconds after typing first sentence and then begins to type again ...]

OK. Now I'm curious. Just what sort of occupation would you use that sort of stuff in? Seriously ... not taking the piss.

[The_Dover]

surveying, engineering.

[Jamezo]

Decimal is perfectly fine, if you want to piss around with arbitrary and distasteful descriptions of angle!

How about 0.374373125? Real men don't need units.

[Coyote]

How about 0.374373125? Real men don't need units.
Radians right?

[Jamezo]

....you want a prize?

[Brian d marge]

Sorry pished again ...can and will aswer later .. DOver is heading down the same street as you ..be careful with friction ,,there its not an exact science ,,,,

Stephen

Ps I was working in Omiya to day the crumpet was fantastic ( you should see what they are doing with Hotpants and stockings !!!) ,,and there is english beer on tap ,, ( and 30 year old single malt is friggen cheap ,,made in Islay by a fella called goalag or gonad ....)

sober I can be of more help

[The Pastor]

ok math nerds time to shine yet again.

How the flipping jenkins do you convert liters per day to meters per second??

And also kg/s to m/s?

Any help would be awesome.

Rm

[Whynot]

ok math nerds time to shine yet again.

How the flipping jenkins do you convert liters per day to meters per second??

And also kg/s to m/s?

Any help would be awesome.

Rm

try using this :2thumbsup

edit: hang on .... kg/s to m/s
thats mass flow to linear velocity ... ?
you will need to know the density of whatever it is you are measuring to start with ...

liters/day to meters/sec - volume to distance effectively
you will need to specify the size of the pipe/tube/drain or whatever the liquid? is having its speed being measured in

[Whynot]

this should help out a bit

http://www.lerc.nasa.gov/WWW/K-12/airplane/mflow.html

[k14]

ok math nerds time to shine yet again.

How the flipping jenkins do you convert liters per day to meters per second??

And also kg/s to m/s?

Any help would be awesome.

Rm
you sure you havent missed a little thing out there? Maybe supposed to read litres per day to cubic meters per second?

[The Pastor]

Cheers man, but that is a little hard for me to understand.

liquid density = 1170kg/m^3
pipe diameter 30cm
rate 17886070.38 liters per day.

how do I work out the velosity?

[Whynot]

basically it says that

M = r.V.A

where:
mass flow rate = M (kg/s)
density = r
velocity = v
Cross sectional area of the pipe = A

so you need to work out the cross sectional area of the pipe in metres squared.
You will also need to convert your litres per day factor into mass flow

1 litre = 0.001 m3
1 day = 86400 s
M = (kg/s)
Q = (m3/s)

M = r.Q

where M = Mass flow rate
r = density
and Q = Volume flow rate

then just chuck the numbers in and it should come out

easy ;)

[Hitcher]

Hot bath. Bottle of Scotch. Razorblade.

[The Pastor]

basically it says that

M = r.V.A

where:
mass flow rate = M (kg/s)
density = r
velocity = v
Cross sectional area of the pipe = A

so you need to work out the cross sectional area of the pipe in metres squared.
You will also need to convert your litres per day factor into mass flow

1 litre = 0.001 m3
1 day = 86400 s
M = (kg/s)
Q = (m3/s)

M = r.Q

where M = Mass flow rate
r = density
and Q = Volume flow rate

then just chuck the numbers in and it should come out

easy ;)

Cheers so much man would you mind checking out my working?

Given data
viscosity 6.3 x 10^-3 kg/m/s
Density 1170kg/m^3
flow rate 17886070.38 L/day
pipe diamerter 30 cm

First I got the flow rate into m^3
17886070.38*.001 = 17886.07038

then m^3 per second

17886.07038 / 86400 =0.207014703472 =M

from M/rA =V

0.207014703472/(1170(pi*(.3*.3/4) = 2.928m/s?

so V = 2.928m/s?

Or am I way off here?

[Whynot]

simplified a bit ...

V = M/(r.A)

therefore

V = r.Q/(r.A)

V = Q/A

hence velocity = volume flow rate / Area

[Whynot]

Cheers so much man would you mind checking out my working?

Given data
viscosity 6.3 x 10^-3 kg/m/s
Density 1170kg/m^3
flow rate 17886070.38 L/day
pipe diamerter 30 cm

First I got the flow rate into m^3
17886070.38*.001 = 17886.07038

then m^3 per second

17886.07038 / 86400 =0.207014703472 =M

from M/rA =V

0.207014703472/(1170(pi*(.3*.3/4) = 2.928m/s?

so V = 2.928m/s?

Or am I way off here?

yea looks ok to me ... does the answer sound right ?

[The Pastor]

yep thank heaps aye,

[Hitcher]

Presumably 30cm is the internal diameter of the pipe? Given the lack of data to the contrary, I presume that it is a perfect pipe i.e. no head loss due to friction?

[The Pastor]

yeah internal diameter and yeah no head loss due to friction.

The velocity is only part of it, im trying to workout if the flow is turbulent or lamminar.

Should get there now I think!

[Jamezo]

Irrelevant; if you're given the fixed flow by volume, then it doesn't matter in the slightest HOW its flowing.

pipe diameter 30cm
rate 17886070.38 liters per day.

That is all the information required to calculate a linear flow rate.

Edit: actually, it's your question, so it may not be irrelevant. now that you have the linear flow velocity, you could derive the viscosities/frictions in reverse.

[The Pastor]

Im working out if the flow is turbulant or not the forumla needs it in m/s to work (as you may of guessed im not smart enough to adjust the formula to suit L/day... ) :D

[The Pastor]

Alright time for another brain buster!

Basicly its the first part to the question in the photo, ive looked at all my text books but I can't seem to find any relevant info.

This question has been taken from an old exam, its in every exam from 2000-2005 so I think it will be in the exam I have to sit tomorrow!

So can anyone figure this one out? The first part would be the best help cheers :D

[thealmightytaco]

Alright time for another brain buster!

Basicly its the first part to the question in the photo, ive looked at all my text books but I can't seem to find any relevant info.

This question has been taken from an old exam, its in every exam from 2000-2005 so I think it will be in the exam I have to sit tomorrow!

So can anyone figure this one out? The first part would be the best help cheers :D

Just Bernoulli's Eq. init? I havent looked at fluids in a long while, can't remember the equation exactly but it relates pressures to velocities, and your mass flow rate and change in section will give you the new velocity, and hence the pressure at 2. Or some such thing. And then the same idea but backwards for the next part.

[Laava]

That is a trick question! It clearly shows an empty bottle lying on it's side. A trip to the fridge is in order!:drinkup:

[The Pastor]

Just Bernoulli's Eq. init? I havent looked at fluids in a long while, can't remember the equation exactly but it relates pressures to velocities, and your mass flow rate and change in section will give you the new velocity, and hence the pressure at 2. Or some such thing. And then the same idea but backwards for the next part.

Yeah I guess so, but you don't know what fluid is flowing and its denisty value as part of bernoulli's is pressure divided by density times gravity...

[Brian d marge]

Poosibly to late now but its benoulis and the density is given as it says water , all you are doing Is solving bernoulis for the dia of the pipe.

plug every thing into bernoulis in its bas form and you will see...

Is that Ar#$%&7e still doing exam questions ....ask Eric about the the buckling question he got ,,,

They smoke FARRRR to much up there in Wellington NCQA offices

Stephen

[The Pastor]

OIC I was looking every where in the words that it was water but couldnt find it! Good thing Im on KB 30min before my exam! Cheers mate!