?

This crazy idea of removing the community vote has resulted in a huge queue of open questions, because most askers do not choose a best answer.

As a responsible member of the yahoo community I have been searching for long-standing unresolved questions in my field so I could help to choose a best answer.

Now the community vote has been removed I can no longer do this.

Now when I go to choose questions to answer I am finding Old q's the asker has forgotten about, or are now redundant.

This question is a test to see how the system responds. Thanks for your help and input.

My PC seems to be running very slow. Its not heavily loaded with files and there is plenty free space on the drive.

I did the usual -chkdsk /f (no problems found) and defrag.

Then I installed Moo0; and in use Moo0 reports an HDD bottleneck.

The Drive is a Samsung SpinPoint HD502IJ SATA 3G drive, and SMART results are all fine.

"Disk thruput tester"

http://www.raymond.cc/blog/download/did/2757/

reports transfer rates of 50MB/s

System: Alive NF7G mobo, 4G ram, Athlon 64 X2 5000+, windows XP SP3

Can you check my work please?

The energy E needed to spin up a flywheel from rest is E = 0.5 I ω ^2

where I is the moment of inertia and ω is the new speed. (in radians/sec)

Lets look at spinning up a lathe chuck to 400 rpm.

400 rpm = 400 * 2 * pi / 60 = 42 radians per second.

I = 0.5 m r^2. so a 10kg chuck of 0.2m dia has I = 0.5 *10 *0.1^2 = 0.05

E = 0.5 * 0.05 * 42^2 = 44.1 Joules. To get this up to speed in 10 seconds uses 44.1/10 = 4.41 Watts.

I cant believe a 5W motor would be able to do this. Is my woking right?

I have a 3.6kW solar panel array. I have recorded data (excel spreadsheet) that shows the power received during each quarter hour, month on month. The readings during cooler months range between zero and 0.5kW (*4 = 2kWh). I aim to build a device that will turn on a heater when there is enough power being generated.

I wish to find the single power level that will enable me to get the best value from the "free" electricity.

if I choose a 1W heater it will be nearly always on, but not generate much heat.

If I choose a 2kW heater it will generate lots of heat when its on - but that will be VERY infrequent.

How do I analyse the data to find the heater rating that will optimize power * total "on time" ?

There is more explanation here

http://www.skillbank.co.uk/arduino/control.htm

I've migrated some accounts from OE to thunderbird. I have 9 accounts.

The server settings are all set to collect mail when I open TB.

It collects mail correctly from the first 8 when it starts.

It doesnt collect mail from the ninth.

When I click "get mail" it collects mail correctly from the first 8 accounts - not the ninth.

When I use the drop-down and click to get mail from the ninth account it does - it works fine.

I've put this on the mozilla forum but no answers.

Can you help?

Best letter sequence to show font characteristics?

I'm looking for a short sequence of letters that will show the characteristics of my installed typefaces.

I dont really want to use more than 20 characters or so. It will need to have lower case, caps and numbers.

Any suggestions welcome.

Suppose the earth is flat.

There are many ways to transform a sphere onto a flat surface, e.g. the Peters and Mercator projections.

However an earth with corners or frilly edges is hardly believable.

the diameter is 7900 miles, so the circumference is 7900 * pi() = 24800 miles

So lets do a simple transformation, by allowing the Greenwich.meridian to remain as 12400 miles. This then forms the diameter of a circular flat earth. so the 180 degree meridian (IDL) would be pi/2 times as long i.e. 19500 miles.

You may think - this cant be right - inhabitants at the edges would be dragged off by gravity towards Cameroon on the West coast of Africa. Nonsense. Common experience is that wherever we are, we are held down to the ground beneath us. "Dust we are and to dust returneth"

And if you take a magnet it will stick to the nearest piece of iron, and not go whizzing off to a "better" place!

Now in order to have night and day, and see the sun rising and setting our flat earth must spin like a flipped coin, with its axis along the Greenwich meridian. The periphery at the equator would be tracing out a circle of pi*d = 39000 miles, and travelling at 39000/24 mph = 28600 m/s and experiencing a centripetal acceleration of v^2/r = (28600 m/s)^2 / (r = 12400/2miles = 6200 miles = 10,000,000m)

whence A = 82 m/s^2

A mass of 1kg would experience an attractive force due to gravity of 1 * 9.81 = 9.81 Newtons (or 1kgf)

and a centripetal force of 1 * 82 = 82 Newtons (or 8.4kgf)

So those poor inhabitants would go flying off!

Of course, as above, we know that wont really happen.

I'll be interested in any contributions to extend the scope of this experiment.

A serious question. I enjoy answering questions and hope that I am helping the poser (ie the one that asks the question). However its very dispiriting to put a bit of effort into providing a full detailed and accurate answer, only to find that in many (even most) cases, even months after answering there are no votes at all for best answer. This is true of many different types of question, even when the poser has specifically asked for a response by a deadline. It makes me feel my time and effort was wasted.

Can anyone suggest a solution? I personally feel there should be a penalty (ie a points charge) for failing to grade the answers (ie assign a best answer or no best answer)

I've put this in the Science category because that's the category I'm answering questions in, so its relevant.

I have a 3.68 kW array with a samil power 3300 inverter but i've never seen more than 3.1 kW since it was installed in December last year. Today we have full sun and a clear blue sky and its noon - the array faces almost due south east, with a roof pitch of about 30 deg, so the sun is full on the array. The power reading is 2.7kW

Now the output of the cells is guaranteed within 90% for the first ten years. How can I tell if the array is out of spec?

I have a set of raw data for solar panel output for a whole month. It contains one column with date/time in 15 minute intervals, and the next with output in kWh.

Like this:

01/02/2012 00:00:00 | 0.009

I need to reformat this so that each day of the month starts in a new column - like this

Time | Day 1| Day 2| Day 3 |

00:00:00 | 0.009 | 0.007 | 0.010 |

00:00:15 | 0.001 | 0.002 | 0.012 |

etc.

Can anyone suggest how I could automate this process, either with a simple spreadsheet, a macro. or vba?

A 5kg weight 1m above the floor (PE)

A 45g golf ball travelling at 40 m/s (KE)

A jam doughnut 250kcal (Calories)

A spring compressed 0.1 m by a force of 20kg.

A cup of coffee (black, no sugar) 0.12litres 40 deg above ambient

A Duracell D cell 1.5V 15Amp hours

A bicycle wheel spinning at 10 rps. dia 21cm, mass 0.2kg

I have worked out answers but I don't believe the results - so if someone would be kind enough to check them for me that would be great. I haven't provided the equations or working in case I have one wrong.

While surfing I got a message from an old g/f - from about 20 years ago!

She was sending me xx's and called me sweetheart - but when I started to respond she changed the subject - but still sent x's.

She says she'd like to meet but wont make any arrangements.

I'm in a relationship "its complicated" but I'd still like to meet her (ok and more)

Come on girls give me some help here!

Recently the water in the tank is only getting lukewarm. Electricity co have checked the meter, immersion heatre and thermostat have all been changed (3 new stats!)

I'd appreciate any ideas on what the fault might be. Not the element - its been changed also tested ok.

not the supply or timer - we've nbeen up thru the night to check it.

At wits end, really appreciate ideas.

I'm 60 and I have two teenage (16) kids. We have been on camping holidays before but entertaining them is hard work. I'd like to find somewhere in the UK that they can do some sort of activity during the day, while I enjoy the scenery and sights with my partner.

Grateful for any suggestions

I have PC's programmed to shut down every day at 10pm - using task scheduler to call Brutus shutdown. I need to display a warning message at say 9.55 that will show on screen even if a game or such is running.

Any help would be appreciated.