# trivia question of the day



## Van (Nov 13, 2006)

Heres a question for a test of weird knowledge.

What does the 64 or 56 refer to when talking about Par cans. Maybe it's easier than I thought everybody prove me wrong ? Of course Bill and Ship you are disqualified from answering


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## soundlight (Nov 13, 2006)

1/8ths of an inch. A PAR 64 is 8 inches across, and 8*8=64. A Birdie (PAR16) is 2 inches, so 16 1/8ths of an inch.


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## Chris15 (Nov 13, 2006)

yeah, what soundlight said.

Divide PAR size by 8, multiple by 2.54 and you have the bubble diameter. (We use the metric system )


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## Van (Nov 13, 2006)

**** , That was a lot quicker than I thought ! I didn't think you'd get it that quickly I guess I'll have to think up something harder


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## soundlight (Nov 13, 2006)

I'm known for pulling out the weirdest bits of technical theater trivia.


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## ship (Nov 14, 2006)

oh' oh' me me.. darn...
Nope, great question. Let's all keep this part of the forum alive no matter easy or hard. Brain tease is a brain tease. A #8 screw is #8 by reference to what given it certainly is not an inch or metric decimal. Simple questions illuminate others even if quickly answered by others.


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## propmonkey (Nov 15, 2006)

something to do with the thread spacing


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## ship (Nov 15, 2006)

That would be correct if I specified something like #8-32 but in this case I specified only #8 - could be a drywall screw even.


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## sound_nerd (Nov 15, 2006)

It's the screw diameter, right? I'm not sure of the system of measurement though...


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## SHARYNF (Nov 16, 2006)

This is an example of the wierd way things get classified

If you take the diameter of the head in sixteenths of an inch, take about one and double it you will have the classification
say the head is 6 sixteenths of an inch, that is a 10 


Sharyn


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## SHARYNF (Nov 16, 2006)

Here is another brain teaser

You have a boat floating in a tank of water with a heavy iron beam inside, you drop the beam over the side into the water, does the water rise or fall in the tank?

Sharyn


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## propmonkey (Nov 16, 2006)

neither. the beam displaces the same amount of water in the boat as out.


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## SHARYNF (Nov 16, 2006)

And another

If a Boeing 747 sits on a newly designed runway that consists of of rolling belt so that as the wheels roll forward, the belt also rolls exactly in sync, when the jets are developing full thrust will the 747 take off?

Sharyn


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## propmonkey (Nov 16, 2006)

if i undertand that correctly, it wont move. its like someone running on a treadmill.


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## SHARYNF (Nov 16, 2006)

propmonkey said:


> neither. the beam displaces the same amount of water in the boat as out.



Good guess but not correct, can anyone see the error in the analysis?
Sharyn


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## SHARYNF (Nov 16, 2006)

propmonkey said:


> if i undertand that correctly, it wont move. its like someone running on a treadmill.




Lets see if anyone else has other opinions and why

Sharyn


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## Van (Nov 16, 2006)

SHARYNF said:


> And another
> 
> If a Boeing 747 sits on a newly designed runway that consists of of rolling belt so that as the wheels roll forward, the belt also rolls exactly in sync, when the jets are developing full thrust will the 747 take off?
> 
> Sharyn


 
Relativity, it's a ***** ain't it ?


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## SHARYNF (Nov 16, 2006)

We will have to see how the various answers go, the answers are not as obvious as most people first think  

Sharyn


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## sound_nerd (Nov 16, 2006)

Water falls....the weight of the beam inside the boat makes the water rise, but once dropped in the water there is less pressure area on the water, so it falls.


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## Diarmuid (Nov 16, 2006)

Ok, on the water question:
If my understanding is correct, then when you put something in something else such as a boat, then it doesnt push down and displace as much as it would out of the boat and just in the water. So basically, I think the water would rise, as the iron would probably while in the boat not be totally submurged, and would probably not displace as much as it would if it was submerged. Of course all of that would depend on various things like whether the water had anything like salt in it, making it more boyannt and the shape and make-up of the boat.

On the Boeing question:

If the wheels are rolling exactly in sync, does that mean the wheels on the belt are also rolling forwards, in which case, the Boeing, would probably take off twice as easy as it would be going at its own full speed as well as the full speed of the rubber belt, thus doubling the planes speed; kind of like one of those flat escalator things they have at airports, where you can stand on it and go at a set speed, or you can walk, whilst standing on it and go at about double your normal walking speed. Of course as soon as it leaves the ground, it could come into problems, because of the way its speed would be almost cut by half... but thats another matter.

Diarmuid


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## SHARYNF (Nov 16, 2006)

Discussions are getting better !! still not there yet  
Some of these are probably good questions for physics class 
They are sometimes used in Mensa type questions 

Sharyn


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## bahaha (Nov 16, 2006)

Wouldn't all the wheels involved have to be completely frictionless for the belt to move in sync. Does that have something to do with the answer. It's been too long since i took physics.


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## kingfisher1 (Nov 16, 2006)

a sail boat on hydrofoils is place in a river with 5 knots of current on a day with ten knots of breeze. 
assuming the boat hydroplanes when it reaches 4.5 knots and that normally the boat reaches 4.5 knots when the wind blows 15 knots.
is it faster for the boat to sail up stream or down? justifie your answer.

to see more about the sailing boat teh foiling moth... http://www.youtube.com/watch?v=lyAUc4128QA


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## SHARYNF (Nov 16, 2006)

You can discount friction.

The answer is really simple but easily missed by most people
Hint what makes a plane fly, and how is that effected by the wheels and belt 
Sharyn


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## bahaha (Nov 16, 2006)

Well, planes generate lift by the way air flows over their wings. So if the belt serves like a treadmill and the plane is essentially motionless it will never take off, no mater how fast the wheels and belt is moving.


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## SHARYNF (Nov 16, 2006)

think about it more carefully, most people will give your answer, but why is it not correct?

Sharyn


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## ship (Nov 16, 2006)

SHARYNF said:


> This is an example of the wierd way things get classified
> If you take the diameter of the head in sixteenths of an inch, take about one and double it you will have the classification
> say the head is 6 sixteenths of an inch, that is a 10
> Sharyn



Fascinating... wait, Ur, that can't be right. Consider a heavy hex verses normal hex, or a truss head verses fillister head machine screw, this much less a threaded rod.


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## ship (Nov 16, 2006)

SHARYNF said:


> think about it more carefully, most people will give your answer, but why is it not correct?
> Sharyn


The plane would take off because it's the thrust propelling the plane, not the wheels. A dragster would stay in place because the wheels are pushing it forward. The plane's jet engines instead are the prime mover thus the wheels are just supports and going to spin at what ever speed they are moved at. IN other words, say double the speed tripple the speed etc until they wore out - that plane is still going forward because it's just a support. 


Think a good headwind - draft is better thus actual takeoff speed can be less. The draft does the taking off not the speed the wheels are moving at. - good trick question.


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## SHARYNF (Nov 16, 2006)

Ship (Brian?)
of course is absolutely correct.
Most people make the mistake of thinking of a car, or walking where the power is applied via the wheels or legs to the surface. In a plane the power is applied to the plane, and the wheels really are only to reduce friction with the ground.

SO for instance if you stood on the brakes and the wheels could not turn then you would be testing the thrust of the engines vs the friction created by the brakes and the tires on the surface.

Sharyn


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## SHARYNF (Nov 16, 2006)

So who wants to go back and review the beam in the boat question and offer other explanations of their answer?

Sharyn


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## ship (Nov 16, 2006)

Very good question, sorry for jumping in, should have PM'd instead for a longer life to it. I admidt, and it is (Brian) that I innitially thought it was the reverse of this until I got the hints. 

On the other hand, if there is enough thrust but not enough ability for forward movement sufficient to gain draft, the plane tends to follow gravity or direction of limited thrust - mostly the nose of the plane would tend to follow gravity. Really hard to compensate for thrust in the air however - that thing is going forward on it's base no matter if bolted to the floor or on a treadmill. Could be at an arc up or down but there is forward movement unless it really can't move. 

This plane is taking off anyway no matter the speed of the wheels below it given in some way the wheels and treadmill were not sufficient to compensate for the forward thrust that is doing the propelling foward no matter how fast the wheels are going. Low air pressure and flying into a tail wind perhaps could be sufficient for this not taking off by way of a lack of forward progression. Such a case would still not be a question of the casters, but instead be a question still of the jet propelsion in the air verses that of the base the jet slides upon. The wheels, skids, pontoons or ice skis have limited effect. 


A similar study might be all about air craft carriers in turning into or with the wind, and the slingshot aircraft launchers on some past ships that didn't even have runways.

Still good question and much to think about in understanding why. Heck for me, draft and the pressures involved with wing shape, much less propeller size shape and angle no matter if boat or plane are still just as much Voodo magik as DMX. I get the general point but don't mess with what I don't find the necessity to master.

On the boat, in general it should be boyancy and surface area but the weight of the beam with gravity will also tend to play a factor I would think. This again given hints as to it not being all that simple.

Used to watch on PBS a boat repair TV show often. Learned a lot about such things with that show and in general constantly found tech ideas. Also watched Junkyard Wars a lot and there was lots of science about propellers on it, much less on it and other shows the science about jets and wings for draft/low pressures. Learned more on TV than in science class.


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## SHARYNF (Nov 16, 2006)

The key point in the boat question is

It takes more displacement of water to float an object since this is how it floats even though it is heavy steel boat etc.

So when the beam is in the boat, it is displacing more water (level is higher) because we have the weight of the boat and the weight of the beam. When we throw the beam out of the boat, the level drops and when the beam is in the water on the bottom the water displaced is just for the volume of the object not the extra to float it, SO the water level drops.

Most people think, you are throwing something into the water tank, so the water level will go up, but since you were supporting it by floating it via displacement it is just the opposite.

They are fun brain teasers where your initial thinking is typically false and the answer is counter intuitive.

Sharyn


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## jwl868 (Nov 17, 2006)

Okay, I had to cheat and look up some first principles.

1. For something that floats, the weight of the floating object equals the weight of the water it displaces. (That was the one I didn’t know.)

2. For something that sinks, the volume of the object displaces the same volume of water. (Archimedes principle)

So with steel at 490 lb/cubic feet and water at 62.4 lb/cubic feet. Say the beam in the boat has a volume of 1 cubic foot so it weighs 490 lb. In the boat (see 1), it displaces 490 lb of water, or 7.85 cubic feet of water. So take it out of the boat, the boat rises, and the water level drops for the 7.85 cubic feet. Now drop the beam in the water, and it displaces 1 cubic foot (see 2) and raises the water level. The net change is a 6.85 cubic feet.


(I’m still having trouble grokking the plane problem.)

Joe


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## SHARYNF (Nov 17, 2006)

|Good job Joe, just to clarify it is a drop of 6.85.

Keep thinking on the Plane question ;-) That one usually starts a debate that goes on for ever !

Sharyn


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## jwl868 (Nov 17, 2006)

The Plane problem:

Here’s where I’m having problems: One of Sharynf’s reply was “You can discount friction”. And I may be taking that out of context. Another of Sharynf’s replies was the example of using the brakes on a plane while firing the engines, and the friction of the tires on the runway counter the thrust, so the plane does not move. It seems there are two conflicting assumptions – discount friction or don’t. 

And the original problem statement is perhaps ambiguous: Is it a non-powered belt (like a series of rollers) or a powered belt, like a gym treadmill? I think the original problem is that it’s a non-powered belt, but it says “…a rolling belt…” and “…the belt rolls exactly in sync…”. The latter implies (to me) a powered belt, like a treadmill or people mover. This makes it difficult to answer, but I don’t think it’s meant as a “trick”. [A classic “trick” question is two coins add up to 55 cents and one is not a nickel.] [Or maybe “belt rolls in sync” is a red herring and is to be interpreted otherwise.]

In order for this not to be a “trick” question, I’m going to consider friction. [If there is no friction, the tires simply do not grab, and the treadmill premise goes away. One might as well have a frictionless runway.] So, on a standard concrete runway, brakes on, engine fires: No movement. Next, on a standard runway, brakes off, engines fire, the plane moves, and wheels rotate in response to the friction between the runway and the tires.

Now, the rolling belt runway. First assume a non-powered belt. Now, brakes off and slowly fire up the engine. The plane is not anchored, so the wheel axles are not anchored, so the wheels begin to roll along the belt. The belt is free to move, but so is the plane. The thrust pushes the plane and the wheels roll along the belt, and the belt does not move. Presumably, the plane develops enough speed to take off. [I can’t convince myself about whether air resistance will cause some loss of thrust and hold the plane to some degree, allowing the belt to slip.] Thinking another way: set the brakes and fire up the engine, and the plane moves by causing the belt to roll. 

Now if the powered belt is assumed (“…the belt rolls exactly in sync…”), how does the plane respond? (Never mind how the sensors work, assume they work.) If the plane starts to roll forward because of the friction between the tires and the belt, then the belt, by design, compensates and the plane does not move, by design. Or, consider this: put the plane on the powered belt, put on the plane’s brakes, and turn on the belt (on manual at a constant speed). The plane moves back. Turn on the plane’s engines and plane’s backward progress is slowed, until it finally overcomes the belt speed and moves forward. Switch the belt speed into “automatic” and the plane eventually becomes motionless.

[Am I missing something else in the premise? The whole concept sounds like some government pork barrel project….]


Joe


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## propmonkey (Nov 17, 2006)

are the wheels and belt moving in the same direction? or opposite?


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## SHARYNF (Nov 17, 2006)

The wheels can roll forward and the belt moves forward also and is powered. 
Bit the answer would be the same if the wheels moved forward and the belt moved backwards link on a teadmill

It is not really a trick question, but most people make a basic incorrect assumption that gives them the wrong answer.

Rolling friction of the wheels in not a factor, the tires do grip on the belt. The brakes are not locked, to the wheels are free to turn. The belt is powered so that it moves in the same direction as the wheels are rolling.
SHARYN


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## kingfisher1 (Nov 19, 2006)

the amount of water displace is realitive to the volume of the object, not teh mass, therefore a boat with big heavy thing in it would displace a lot of water, because it has a lot of surface area (if it were a smaller boat, it wouldn't float with the steel in it). by taking the beam out, the boat would rise, and the water would drop. the steel's would make the water level go up but not enough to compensate.
I really wish i had the time to cul through my phsyics notes and give you teh equation for all this, because i think i'd make more sense that way...


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## kingfisher1 (Nov 19, 2006)

and btw, any ideas about our hydrofoils....?


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## Van (Nov 21, 2006)

Ok, New Industry Related Trivia Question of the Day, < he said wrenching the steering wheel to the left so as to get back on track >  

What do you call a person who builds sets for movies, and why are they called that instead of what they really are ???? 

Cryptic enough for you ? anybody got the answer ??


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## kingfisher1 (Nov 21, 2006)

if i were to guess it would be plasterer, (etemologically related to plaster line)


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## Schniapereli (Nov 21, 2006)

I think the film set builders might be called "grips" or maybe that's just the people who move it... (I'm not really a film person)

The plane could not take off. The only thing that matters is the plane's movement in relation to the wind. If it were in a giant wind tunnel, it would take-off. Or, like when you throw a plane, it takes off. But, if there is no wind on the wings, no lift happens. All that matters is the movement in the air.

For the boat question, the water would rise. The weight while in the boat causes the boat to sink more, and add the volume of the air inside it. It is like pushing down on a bowl in the sink while you are washing dishes. The density of the bar makes a lot more pressure pushing down on the boat, and adds more volume in air, than there is volume in the bar. When the bar is in the water, only the volume counts, which is relatively low.

Don't know if you've already answered some of these, but oh well. I just like answering brainteasers regardless of previous input.


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## Van (Nov 22, 2006)

Nope not plasterer, but I see where your'e comming from. Plaster line actually means just that it's where the scenery stops and the "plaster" of the building starts. 
Grip is also a good guess and I have been in theatres where they have referred to their stagehands as "grips" because, as you said, they "grip" the scenery. In the movies Grips are actually a member of the lighting crew. They perform a lot of different jobs but they are primarily associated with set-up and operation of lighting instruments "On-set" background lighting and power supply falls under the auspices of Rigging-electrics. 
Two good guesses though. I'm not giving out hints yet though.


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## Schniapereli (Nov 22, 2006)

SUPERCALIFRAJILISTICEXPIALIDOCIOUS!!! 

Online I got from Wiki, Construction Manager or Head Carpenter depending on what you mean... But I'm guessing I'm totally off.


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## kingfisher1 (Nov 22, 2006)

have anything to do with catherine the great's love pitimkin? the guy who constructed faceades of cities to impress visiting monarchs


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## jwl868 (Nov 22, 2006)

Momentary de-railing:

I tried to ponder the plane problem some more, but I couldn’t find where my logic was failing. So I decided to look up the solution on the Internet. I found several message boards about it (one with 400+ posts!!!). (And I’ve heard better manners at a Steelers-Browns game.) Seems to be a lot of mis-application of concepts [guilty], poorly stated problems open to interpretation (Sharynf’s version seems to be one of several versions of the problem), some red herring issues [the problem is about movement and the airplane is not relevant though the jet engines are relevant; and often variations of the problem statement coax a way of thinking or include a false statement], and the general problem of applying a real world machine (the plane) to a truly imaginary machine (the belted runway) and the interface between the two. But most peculiarly, there seem to be two camps for a problem that is demostratable with mathematics/physics. In fact, someone who has just finished Physics 101 and still remembers free body diagrams is probably in the position to explain/demonstrate it [And its been a loooong time since I did Physics 101]. 

Ignore my earlier post on the subject [I was hung up on the friction component of the problem and the construction the free body diagram.] – The plane flies and some senator gets re-elected for bringing in the massive pork barrel funding for the runway. [The plane is like any other object in motion on a surface; the two opposing vertical forces cancel, and there is a forward thrust force and a backward friction force.] And I’m going to leave it that – this problem has been discussed endlessly at other forums.


Joe

(No clue about the set builders - I never watch the credits that closely..)


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## SHARYNF (Nov 22, 2006)

I posted it here to get the discussion going, and because it does tend to get people to take pretty strong positions.

The basic concept with these sort of questions, sort of like illusions and magic is to distract the reader from the relevant facts, and draw on personal experiences that lead someone to the wrong conclusion

Basically, most of the time when we think of an object moving forward on the ground we think that the movement is produced by the wheels, like a car, or in our personal experience your legs from running.

In a plane unless you stand on the brakes, the wheels really do nothing but reduce friction and the force comes either from the prop or the jet, So if you apply forward thrust, no matter what the belt is doing, the wheels will simply compensate, they might be going twice as fast as the belt, in the opposite direction, in the same direction, it really does not matter, the plane will move forward, air/wing will create lift and the plane will take off.

Sharyn


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## Schniapereli (Nov 22, 2006)

...but it can't take off...
If the plane just sits there on the belt moving backward, it will go backward.
If it is not on a belt, and turns on the engines, it will go forward.
Even though the propellers and jets will be pushing the air, the belt is still pulling back on the wheels. It doesn't matter that the engines are not pushing it forward on the belt, just that it is pushing it forward at all. It is still an equation of subtracting vectors. Still no wind, no lift, no take-off.

Somebody has to try it out on a remote control plane on a treadmil. (if anybody has both.) We need to have a definite answer...


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## Van (Nov 23, 2006)

kingfisher1 said:


> have anything to do with catherine the great's love pitimkin? the guy who constructed faceades of cities to impress visiting monarchs


 
WHAT ? hehehe
No, actually the guys that build sets for movies are actually called Prop builders, or prop makers. It comes from a fight between IATSE and the Construction Carpenters union. Early on the Carpenters union tried to muscle in on the movie industry and force the set builders to join thier union. As we all well know there is a big difference between Set carpentry and construction carpentry, just as there is between a theatrical electrician and a IBEW guy. Yes the basic concepts are the same but application, language and practice sometime differs. So the legal battle ensued and, from what I understand the courts said, " a carp is a carp" and since the Carpentry union had a "specialization" or Designation of Carpenter, the movie industry or IATSE countered by creating the designation of "Prop builder" to get around the legal restricton. 
I love movie work. It's kind of different from the theatre world but it's a blast. The money is not bad either !  

Ok give me a day or two to think up a new one.....


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## ship (Nov 24, 2006)

Schniapereli said:


> ...but it can't take off...
> If the plane just sits there on the belt moving backward, it will go backward.
> If it is not on a belt, and turns on the engines, it will go forward.
> Even though the propellers and jets will be pushing the air, the belt is still pulling back on the wheels. It doesn't matter that the engines are not pushing it forward on the belt, just that it is pushing it forward at all. It is still an equation of subtracting vectors. Still no wind, no lift, no take-off.
> Somebody has to try it out on a remote control plane on a treadmil. (if anybody has both.) We need to have a definite answer...



I think this should become a write in campaign for Mythbusters. They are tech people and would understand how important the answer to this is.


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## ship (Nov 24, 2006)

Van said:


> WHAT ? hehehe
> No, actually the guys that build sets for movies are actually called Prop builders, or prop makers. It comes from a fight between IATSE and the Construction Carpenters union. Early on the Carpenters union tried to muscle in on the movie industry and force the set builders to join thier union. As we all well know there is a big difference between Set carpentry and construction carpentry, just as there is between a theatrical electrician and a IBEW guy. Yes the basic concepts are the same but application, language and practice sometime differs. So the legal battle ensued and, from what I understand the courts said, " a carp is a carp" and since the Carpentry union had a "specialization" or Designation of Carpenter, the movie industry or IATSE countered by creating the designation of "Prop builder" to get around the legal restricton.
> I love movie work. It's kind of different from the theatre world but it's a blast. The money is not bad either !
> Ok give me a day or two to think up a new one.....



You mean that if the Teamsters dump a small stack of 1x4 lumber off their forks or a fork lift by way of being an idiot, and neither he nor the assistant driver there to adjust the forks and riding on the fork truck in a un-professional way to do nothing else but this won't pick up the lumber they dumped due to incompitence; it than becomes a debate weather because it's lumber, the carpenters pick it up, or because it's crap on the deck, the laborers pick it up, it might cause an hour of wasted time because the idiot who dumped the crap off the forks won't just pick it up?

I can't believe there is union battlels of who does what. Can't we all just get along?


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## Van (Nov 25, 2006)

Yeah unless you are just driving a "gator" across the set you better have a teamster driving you. Honestly you aren't too far wrong. As a "Rigger" < rigging electrics in the movies > you have to be real careful when build thing to run cables with. If it's a big project you might need to be going to the prop builders to get it done instead of just building it yourself.


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## Van (Dec 4, 2006)

How About a new question of the day ? Who can be the firsat to properly name all seven parts of a "Standard" flat < kicking it old school>


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## ship (Dec 4, 2006)

I will not answer the question but help to refine it as a "Soft Flat." Old school and clout nails still are tops.


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## Lightingguy32 (Dec 5, 2006)

all PAR, R, and MR, type lamps are classified this way, the number being 64,56,16 or what ever else means the number divided by 8 (eighths of an inch)
so a PAR 64 is 8" in diameter, a PAR 56 is 7" in Diameter and an MR-16 is 2" in diameter


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## scarlco (Dec 11, 2006)

Van said:


> How About a new question of the day ? Who can be the firsat to properly name all seven parts of a "Standard" flat < kicking it old school>



Seven parts? Uh...

1. Top Rail
2. Bottom Rail
3. Toggle Rail
4. Corner Block
5. Stile
6. Strap
7. Keystone
8. Diagonal Brace
9. Half-Strap

I think that covers it... maybe.


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## Van (Dec 11, 2006)

scarlco said:


> Seven parts? Uh...
> 
> 1. Top Rail
> 2. Bottom Rail
> ...


 
Yeah seven the strap and half strap aren't part of the basics but good job this question has only sat here for two weeks. Great now I have to think of another !


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## kingfisher1 (Dec 11, 2006)

heres a quick easy one.
What does it mean to "cheat out" 
and "block"


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## Schniapereli (Dec 11, 2006)

Cheating is when actors in a conversation really face out a little toward the audience, sort of making a V facing downstage, instead of being parallel ll.

Blocking isdeciding where on the stage something happens. Could be when they are acting, or singing, or dancing.

Don't know if this is outstandingly easy, (probably is...no, I'm sure it is...I'll ask anyways...) but who was the first to use a "memory" or computer lighting board, what was that board, and for what play. =P


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## Logos (Dec 11, 2006)

As far as I know the worlds first "memory board" was the Strand IDM/MSR developed in 1968 and installed in Schweinfurt Germany, the Budapest Opera and the London Coliseum in that year. I have no idea who (individual designer) first operated it or what shows it was first used on.


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## Logos (Dec 11, 2006)

As a postscript I've used the M24 (it's grandson or great grandson) as recently as Ocober this year. Still works although it's a bit creaky.


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## Van (Dec 11, 2006)

Schniapereli said:


> Cheating is when actors in a conversation really face out a little toward the audience, sort of making a V facing downstage, instead of being parallel ll.
> 
> Blocking isdeciding where on the stage something happens. Could be when they are acting, or singing, or dancing.
> 
> Don't know if this is outstandingly easy, (probably is...no, I'm sure it is...I'll ask anyways...) but who was the first to use a "memory" or computer lighting board, what was that board, and for what play. =P


I'm removing myself from this question 'cause he's design the next production on our stage That is if you are refering to the first "computerized " memory board. The first "Memory" boards were mechanical and had some big 'ole lock bolts on them where you could set a "level" you also had a Master handle that locked onto the individual handles and you might have had to push or pull 10 handles at once it was tough work. if you every get a chance to look at a real "piano Board" it's something else. There is one in Oklahoma city in the Scottish Rite Temple the is still used and in perfect " Showroom" condition.


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## Schniapereli (Dec 12, 2006)

I probably didn't phrase that as best as I could....

By memory board, I mean a computer that sends a message to a dimmer rack via DMX, and all that good stuff. The kind with a screen and buttons. (1st to have a memory, and store cues...)
And, by first ever, I meant in Broadway...
I don't know who actually first ran it on Broadway, but the designer was the first to ask for one on their show.


I have only seen pictures of the really old kinds, and wow, I am glad I don't have to run something like that nowadays... It would be awesome to see one in real life though...especially in such good condition... Iv'e never been able to see much historic equipment besides that in the dusty corners of our storage piles...(I'm just a high school tech, and haven't gone to too many other theaters. I have never actually seen a play outside of school. I've tried, but didn't have enough money, or just missed them entirely...)


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## Diarmuid (Dec 12, 2006)

I dont know whether this is right, but was the EDI LS-8 the first memory console on broadway... It was a memory console used in the broadway musical 'A chorus line'. When the show transferred to Broadway, the Lighting Designer Tharon Musser was allowed anything she wanted and so she asked for a memory console, the Strand version wasn't ready, but the LS-8 made by EDI (Electronics Diversified) was almost ready. However to run it the operating system had to be loaded from paper tape, but the memory was non-volatile and so the cues once saved would stay there. However you did say that the question was one reffering to a desk with DMX capabilities, but the DMX standard wasn't introduced until 1986, about 11 years after the first memory console on broadway (1975).

Hmmm... good question and good thread!! 

Diarmuid


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## Van (Dec 12, 2006)

Schniapereli said:


> I probably didn't phrase that as best as I could....
> 
> By memory board, I mean a computer that sends a message to a dimmer rack via DMX, and all that good stuff. The kind with a screen and buttons. (1st to have a memory, and store cues...)
> And, by first ever, I meant in Broadway...
> ...


 
It did not utilize DMX but it was a "computer memory" console. 


_I dont know whether this is right, but was the EDI LS-8 the first memory console on broadway... It was a memory console used in the broadway musical 'A chorus line'. When the show transferred to Broadway, the Lighting Designer Tharon Musser was allowed anything she wanted and so she asked for a memory console, the Strand version wasn't ready, but the LS-8 made by EDI (Electronics Diversified) was almost ready. However to run it the operating system had to be loaded from paper tape, but the memory was non-volatile and so the cues once saved would stay there. However you did say that the question was one reffering to a desk with DMX capabilities, but the DMX standard wasn't introduced until 1986, about 11 years after the first memory console on broadway (1975).

Hmmm... good question and good thread!! 

Diarmuid_

The Lighting designer was Tharon Musser. The designer of the Board was Gordan Pearlman. He also invented the worlds first "digital" dimmer, was instrumental in the design of the original SCRIMMER dimmer and later founded E.T.which produces IPS and the Horizon system.
He's currently Desinging our next Mainstage production " Vanya " an adaptation of the Chekoff originally produced at the Citadel and having it's premier in the States here at A.R.T. Oh and Starring Our own Artistic Director Allen Nause, and Oscar winner, < and freind of ART> William Hurt. < God I love shameless name dropping, it's the best thing about this bussiness> 

P.S. tickets availible today at www.Artistsrep.org


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## SHARYNF (Dec 12, 2006)

DMX came much later.Most of the early advanced dimmers use an analog signal typically 0-10 volts, the dimmer in essence took this voltave signal and used it as the percentate of the power to pass along to the output. and there was a direct connection of the signal to each channel of the dimmer the old Cinch Jones analog connectors were typical for this type of system. Then things moved along to a analog signal that the all the dimmers on the connection looked at, and determined if the signal was for that dimmer or not, Strands AMX and NSI MPX works like this. It was only with DMX that you had a digital signal, and now with ethernet based systems it is getting even more advanced since a dimmer is really a network device that is addressable, and able to accept a data packet with information for it it use for control

Sharyn


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## Schniapereli (Dec 13, 2006)

..well while we're talking about DMX, and ACN...

Does anybody know if in the far future they might make a system that works with USB, or maybe Firewire? Wouldn't that be a lor faster, or would it not be worth it?
...just random wonderings...


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## Foxinabox10 (Dec 13, 2006)

Both of those have maximum lengths without using repeaters that are fairly lower than DMX. USB is 16 feet and Firewire is 164 feet I believe.


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## Chris15 (Dec 13, 2006)

Not just the comment about repeaters and cable lengths that Footer made, but would there actually be any real benefit to doing so? It is not like there is a huge amount of data being transferred...


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## SHARYNF (Dec 13, 2006)

the likely hood is that it will be a straight ethernet connection, and that the dimmer will simply look like a node on the network, and have an ip address etc, and run over 10base t or 100base t and simply eliminate the need for a conversion to dmx, the console will simply send an ip packet and the dimmer will simply receive it and decode it
Sharyn


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## Van (Dec 13, 2006)

SHARYNF said:


> the likely hood is that it will be a straight ethernet connection, and that the dimmer will simply look like a node on the network, and have an ip address etc, and run over 10base t or 100base t and simply eliminate the need for a conversion to dmx, the console will simply send an ip packet and the dimmer will simply receive it and decode it
> Sharyn


 
Actually there is an ET system in place that uses a similar technology Their Vista architectual systems have multiple hosts implanted on individual relays and modules in the rack and can be addressed individually. Personally I never really saw the need. I'm quite happy with DMX as a control protocol. I can see some reasons, say certain automated fixtures, that you might want to go to a TCP/IP protocol. but for the stability that dmx offers over ethernet, I dont really see the advantages at this state. Oh yeah just my $.02


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## SHARYNF (Dec 13, 2006)

Putting in my .02 I can agree with you and also disagree 

The big thing that the whole cat5 10baset stuff gives you is a much cheaper cable spec, and all the ic's to do the interface are standard, available and much cheaper. Dmx is really picky about termination first, cable length and spec second and also drivers and a lot of that goes away or becomes less problematic if you move to ethernet.

The other big thing is ethernet allows for better error detection, correction retransmission, switching etc etc, so based on addressing you have a lot more flexibility on how to wire things up, you don't need daisy chaining, etc

It really is down at the lower physical levels that the move away from the traditional dmx probably makes more sense
Sharyn


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## Andrewr (Dec 15, 2006)

Actually I believe the point of ACN is to move everything above the hardware level when it comes to data transmission.

Ethernet is actually (IIRC) 7 levels of hardware/software. ACN sits at the 2nd layer and will send DMX (or RDM, or anything else people invent) (an 1st layer doobry) along the 'network' (which could be made of wet string, or be the internet) independant of the hardware setup.

To get even more OT, ACN is really about moving DMX away from the hardware in the same way Windows moved everything above a hardware abstraction level.

Only problem so far is existing solutions use things like broadcast packets. Which tend to make the IT guys come shout at you. 


What was the question again?


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## Van (Dec 15, 2006)

Andrewr said:


> (which could be made of wet string, or be the internet)
> 
> What was the question again?


 
Wet string......... Ok I'm LOL .

I think your'e right it is the dry english humor


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## SHARYNF (Dec 16, 2006)

Andrewr said:


> Actually I believe the point of ACN is to move everything above the hardware level when it comes to data transmission.
> Ethernet is actually (IIRC) 7 levels of hardware/software. ACN sits at the 2nd layer and will send DMX (or RDM, or anything else people invent) (an 1st layer doobry) along the 'network' (which could be made of wet string, or be the internet) independant of the hardware setup.
> To get even more OT, ACN is really about moving DMX away from the hardware in the same way Windows moved everything above a hardware abstraction level.
> Only problem so far is existing solutions use things like broadcast packets. Which tend to make the IT guys come shout at you.
> What was the question again?



You are correct but I think misinterpreted what I was saying. Basically the move to ethernet will see the greatest changes at the physical layer, because it moves DMX up in the ISO model, allowing for the use of 
cat5 and above, switches, etc
Sharyn


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## Andrewr (Dec 16, 2006)

OOO, ditto!

The point I was trying to make is that ACN will make DMX a purely software issue. So yes we will be replacing some (and eventually all) of our DMX cabling with networking type stuff. But the bigger change is that we will never need to do it again.
No change in cabling for any protocol ever again. Thats the goal.


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## cutlunch (Dec 16, 2006)

Just a little point CAT5 has already been cleared to carry DMX512 signals over without needing to convert it to ethernet.

If I was doing a new installation I would wire in ethernet connections but until my budget could afford it I would just use them for DMX512.

SharynF has made the comment about reliability of ethernet components. I still think that any time you add another powered device in your control chain it's another device that can fail.

In DMX512 without using ethernet you have only two main sources of problems - the cable / connector and the signal souce /dmx splitter.

Except for integrating multimedia into a production I can't see a major need for it in High Schools. 

If someone does have an ethernet DMX system in their venue could they plaese tell me what it is used for. Also what actual difference it has made compared to a purely physical DMX system.

I do believe there is a place for it but at what level of venue I don't know.


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## SHARYNF (Dec 16, 2006)

Here are the main differences

One if you run more than 32 devices on a channel you should get a repeater/splitter for DMX and you should have an opto isolator, so IMO you wind up with additional powered devices anyway

You have the ability to run far more cable before you run into problems

You can have star type configurations much more easily.

If all you are doing is running a dmx line to a dimmer rack, then it probably does not matter, but once you start to put movers, and other dmx devices around it is a big help

DMX cable is not cheap, cat5 is dirt cheap, I agree you can use cat5 cable, a lot of people keep saying you can BUT...

It really comes down to wiring infrastructure, and the ability to expand and be flexible. In construction, people are much more used to running cat5 these days than pulling dmx cable


In theory if the move is to a true ethernet based system, then you gain all the advantages of error detection, correction, retransmission, and addressing each device individually vs each device in essence counting the transmission to determine if it is for that device.

Sharyn


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## Chris15 (Dec 18, 2006)

Don't know what others think, but I do wonder whether the statement along the lines of never having to replace the cabling again will actually hold true. I mean networking started with what 50 ohm coax, then went to Cat5, then Cat5E, now Cat 6. I have to wonder whether there will be a newer and better cable at some point in the not too distant future. I guess if you installed fibre the you would have a better chance of future proofing but I do have to wonder...


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