Spyman

Under My Settings / Notification Options / Profiles & Friends you can change how the system should "Notify me when I have a pending friend request".

I can confirm that there is one member, (not me), having TonyMcC listed as a friend with his picture and link, that is not listed on his profile.

I don't understand, you have eight friends on your profile page and they all have your name and picture on their profile. If your browser is not updating properly try [Ctrl] and [F5] simultaneously to force a new update.

How a magnetic compass works

The gravitational pull from the engine oil in one tiny motor is negligible compared to the whole Earth's mass. No, space is very very very empty.

Gas is matter and attracts itself.

As I interpreted John Cuthber's example, there would suddenly be common knowledge from a God. The start time is needed, if everyone don't start acting on the same day, no islander can derive anything on his own counting. I think the quiz in the OP assumes only two eye colours and in the OP's answer those with brown eyes commit suicide the next day. Well, I think the assumption is valid, can you show how the society in the OP dies early without introducing new stuff?

Registering two accounts might suffice...

That would be one different way to set up an synchronization, but that information is not included in the original quiz. The initial conditions in the asked quiz does not include a syncronization point and it is also assumed that the society can last. No, one thousand persons living their lives on an island will not individually realise their circumstances simultaneously. No, it is not enough with common knowledge, if they don't know if they count from the same day then they can't make any valid conclusions. It's possible to set up a lot of different things that happened a year before he arrived, but that is not what is asked for.

I count to four persons but only three artistic fields, which means the question given can not be fully answered. (You are only allowed to vote once on a single post.)

FYI members can only vote once on any single post and further more only give one negative vote each day.

"Stars are thought to form inside giant clouds of cold molecular hydrogen-giant molecular clouds roughly 300,000 times the mass of the Sun and 20 parsecs in diameter. Over millions of years giant molecular clouds are prone to collapse and fragmentation. These fragments then form small, dense cores which in turn collapse into stars. The cores range in mass from a fraction to several times that of the Sun and are called protostellar (protosolar) nebulae. They possess diameters of 0.01-0.1 pc (2,000-20,000 AU) and a particle number density of roughly 10,000 to 100,000 cm−3. The initial collapse of a solar-mass protostellar nebula takes around 100,000 years." http://en.wikipedia.org/wiki/Nebular_hypothesis#Formation_of_stars_and_protoplanetary_disks If you look backwards in time on the "ever expanding universe", you will see that 13.7 billions years ago the gasses were not so thin at all.

Galaxies don't take turns to form, they form independently in parallel, if one can form in 500 million years then infinite galaxies can form simultaneously.

It is NOT the knowledge of that there exists islanders with blue eyes that sets this off, it is the synchronization of all islanders simultaneously with the shared knowledge that all others also are synchronizated. Since they where forbidden by their religion to discuss eye-colour an outsider is necessary for this synchronization to ever happen.

Are you sure? Maybe I did something wrong but I got it to roughly 2 microseconds slower each day.

There are lots of different batteries with different properties, connecting two very different batteries to each other might very well damage them both. There are many different types of electromagnets like pushing, pulling, turning or holding and so forth. A "power to hold" electromagnet is without a permanent magnet and therefore don't have a magnetic field that can hold on to anything without the electrical current. The opposite is a "power to release" electromagnet that have a permanent magnet built in that holds the load continuously without power and then the electrical current overcomes the magnetic field to release. The permanent magnet in a holding electromagnet holds on as long as a any normal magnet holds on, (which is very long), and has a magnetic field even if there is nothing for it to hold, just as any normal magnets.

I sounds as you need a battery operated solenoid, search the web for different models and brands that you can use.

It sounds as the air chambers are separated from the firebox, if so then heat first transfers internally through the walls to the air chamber.

What is a "Flying City"? If we are talking about a Space Colony like this: A space habitat (also called an orbital colony, or a space colony, city, or settlement) is a space station intended as a permanent settlement rather than as a simple waystation or other specialized facility. No space habitats have yet been constructed, but many design proposals have been made with varying degrees of realism by both engineers and science fiction authors. http://en.wikipedia.org/wiki/Space_habitat Then IMHO the best we can think of today is some variant of a Bernal sphere: A Bernal sphere is a type of space habitat intended as a long-term home for permanent residents, first proposed in 1929 by John Desmond Bernal. Bernal's original proposal described a hollow spherical shell 1.6 km (0.99 mi) in diameter, with a target population of 20,000 to 30,000 people. The Bernal sphere would be filled with air. http://en.wikipedia.org/wiki/Bernal_sphere THE DESIGN AND VISUALIZATION OF A SPACE BIOSPHERE Lewis One is a qualitative space biosphere design. It is intended to house 10,000 residents in a cylinder large enough for a 1g rotating habitat module and construction facilities to reproduce the module. The shielding, exterior, and construction bays are non-rotating. Lewis One is compared to the Bernal Sphere space colony designed in the 1970s. Lewis One is visualized using state of the art computer graphics hardware and software to roduce a three dimensional, animated, lighted, shaded, texture mapped surface model. http://www.nas.nasa.gov/assets/pdf/techreports/1991/rnr-91-018.pdf

You can buy a regulated power supply where it's possible to control the output voltage and current to a specific value. It will hold the desired values nearly constant despite variations in the load.

As ewmon is saying you need to choke the current to your electromagnet so that it gets inside the maximum rating of your power supply unit, I would use a 24 ohm resistor in series which would give a current of around 1 amps. But make sure you use a power resistor that can dissipate the waste heat, it will get very hot and needs to have a rating of at least 24 watt to not overheat.

I still don't understand what you are trying to do, but there is a difference if you have a time/distance diagram describing the movement of ONE object through several different phases or if you have a time/distance diagram describing ONE shot of several idividual objects in their respective different phase.

Sorry if I was unclear Michel. You can use the data from a distance/time diagram to create a distance/velocity diagram. If you take the data from your distance/time diagram in post #72 and make a distance/velocity diagram, how does it look? I will repeat the data for you here: t=1s v=1m/s l=0.5m t=2s v=2m/s l=2.0m t=3s v=3m/s l=4.5m As you can see the values for time and speed are conveniently equal. Now please tell me if the data in your curve from post #72 have velocity proportional to distance?

You already made it: Since you have declared that: We know the speed at T1, T2 and T3, simply replace 1s with 1m/s, 2s with 2m/s and 3s with 3m/s. Is velocity proportional to distance?

We must have misunderstood each other, I never ment to say that there was not a rate of change of velocity. Yes, of course it is a curve, but the important question is: Is velocity proportional to distance in it?