Slashback: Boeing, Fraud, Fundage 210
Next they'll tell us they're not involved with Areas 51-63! Louis_Wu writes: "Space.com says that Boeing isn't really working on Anti-Gravity, regardless of previous news from the the BBC or Jane's Defence. It seems that the rumors spread because some people in Boeing were thinking of developing a relationship with the Russian scientist who did anti-grav research a few years ago, Dr. Evgeny Podkletnov.
Boeing spokesman:
'The recent report that we are [involved in anti-grav research] is based on a misinterpretation of information. For instance, GRASP is not a codename for a current project but rather an acronym for a presentation entitled "Gravity Research for Advanced Space Propulsion," in which a Boeing engineer explains Podkletnov's theory and proposes that we should continue to monitor this work and perhaps even conduct some low-cost experiments to further assess its plausibility. No steps have been taken beyond this point by Boeing.'
Jane's also mentions theorized weapons 'capable of producing a beam of "gravity-like" energy that can exert an instantaneous force of 1,000g [1000 Gravities, not grams] on any object -- enough, in principle, to vaporise it, especially if the object is moving at high speed.'
Don't tell Einstein. :)"
And here's the part where I skip town.
Planetes writes "The Florida Times Union (Jacksonville, FL) has an interesting article about a lab testing company that has discounted his claims about some technology previously discussed on /.
Personal favorite paragraph:
'Lawyers for the company, Intertek Testing Services, discounted almost every aspect of a three-page letter that appears to validate an invention that sends high-speed data over electrical power lines. The letter is addressed to Madison Priest, a St. Augustine man whose disputed communications technologies were the subject of a sweeping Times-Union investigation this year.'"
Not at all what he said. knorthern knight writes: "Crow tastes icky, but here goes. Since I submitted the original citing about the story in The Register, ISPAI have sent a polite note to me. Here it is ...
Subject: ISPAI Reaction on HT News Item dated 27th July '02Dear Sir,
This is in reference to the front page news article by the Hindustan Times dtd: 27/07/02. Mr Amitabh Singhal, Secretary, ISPAI has denied having made any statements favoring blocking of sites by Indian ISPs.In reply to Mr. Singhal's letter to Hindustan Times,(copy enclosed) the HT has released the following news clipping at today's news paper http://www.hindustantimes.com/news/printedition/01 0802/detECO07.shtml
This is for your informaton and necessary action please.
With regards,
Puneet Tiwari Sr. Executive -ISPAI"
Behind every horde of enemy attackers are the people who thought them up. Anonymous Coward writes "I've finally posted the game binaries and source code to the Indie Game Jam games. The Indie Game Jam is a yearly game design and programming event designed to encourage experimentation and innovation in the game industry. 14 professional game developers created 12 experimental and innovative games in 4 days! The source to the engine and all the game code is GPLed on SourceForge, so enjoy. Remember, they're experimental and a bit rough, not commercial quality games."
One Blender you can buy for forever. kabir writes "The Blender Fund is up around 65K Euro right now... so close, yet still so far! This would be a great time for anyone who was on the fence about donating (wondering if the fund would make it, etc.) to pitch in and help put us over the top." Here's our previous story about this effort to liberate the Blender source. Does anyone have a business which might see a donation here as a good long-term investment?
Boeing and Anti-gravity (Score:1)
Gravities? (Score:3, Funny)
For those of you not accustomed to metric, 1 Gravity is equivalent to 35 Pressures, 18 Forces, 340 Micro-lengths, 2 electromagnetisms, or 42 CowboyNeals.
Re:Gravities? (Score:1, Funny)
So that's like, what, 50 tons?
Re:Gravities? (Score:2)
Only problem is, that's not that much energy. Gravity is a very weak force, IIRC (again, many years since I studied this stuff for a grade).
--
Evan (no reference here)
Re:Gravities? (Score:3, Informative)
mass accelleration (Score:2)
Actually, if you want to get technical, 1G only accelerates masses at 9.81 m/s2 at 1 earth radius... and slower at distances farther away.
Re:mass accelleration (Score:2)
That's it. No magic. 1G *always* accelerates mass at 9.81 m/s^2 (rounded). If the acceleration is something else, whatever is being accelerated isn't experiencing a net force of 1G.
The value is pinned. It isn't variable over the earth's surface in accordance to the proximity to more dense matter in the earth. Yes its value was chosen to be pretty much the force you feel on the surface of the earth.
Re:mass accelleration (Score:2)
The value for little g - "standard acceleration of gravity" is fixed. 1g does not depend on where on earth you are - or how far from earth you are. The value is always the same because it was chosen for convenience. Look it up. Some scientists got together and said "Hey, let's define this value as being 1g - it mostly works most of the time".
Re:Gravities? (Score:5, Informative)
To clear some things up, 1G is not even in m/s^2 units. 'g' a.k.a. "little g" is ~9.8m/s^2 (so that mass*g is a force, kg*m/s^2), but 'G', a.k.a. "big G", is, ~6.67*10^-11 m^3/kg/s^2 (in mks).
The confusion is that 'g' is the acceleration due to gravity close to the earth, while 'G' is the universal gravitational constant. It is a constant that is used to derive little 'g'. The relationship can be explaied in a couple of steps.
F=G*m1*m2/r^2
m1 = mass of object 1,
m2 = mass of object 2
r = distance separating objects 1 and 2
m2 = mass of random object, such as a super-ball, m
r = radius of Earth, R
g = G*M/R^2
Re:Gravities? (Score:2)
(And you can look at it either as a unit of acceleration -- how it's usually used -- or as a field strength indicator -- 1 G exerts a force of 10 newtons on a 1 kg mass.)
Re:Gravities? (Score:2)
Re:Gravities? (Score:2)
Re:Gravities? (Score:2)
Re:Gravities? (Score:2)
(Not that Christians are all that keen on the laws of Thermodynamics, but I suppose you HINT HINT wanted this link posted.)
Adventures with Chickens developed by RockSolidSoftware is a whimsical Christian
action/puzzle/adventure game for the Windows 95/DirectX platform. Your goal is to
rescue purple Chickens from suffocating in the harsh confines of deep space.
Along the way you get a healthy dose of scripture!
http://www.xgames3d.com/prchick.htm [xgames3d.com]
Features
Edutainment - Learn the Bible as you play.
Non-Violent Christian based gameplay for the whole family.
High Resolution graphics and DirectX.
Digital sound FX and music.
Supports different difficulty levels and pieces to play with.
25 levels in Registered Version.
(On the upside the Space Chickens are flash frozen in the cold depths of space.)
Re:Gravities? (Score:2)
Ah. I love Americans.
and check this [snopes.com]
Re:Gravities? (Score:2)
Gravity may be pretty weak, but the earth is pretty big
BTW 1 gravity = 1 force, eg 1 lb * gravity = 1 lb force.
Re:Gravities? (Score:2)
Originally, weight stood indifferently for what we call mass and force. The equation F=mg actually defines the constant g, which separates Force from Mass.
That g varies from place to place can be demonstrated by a spring balance.
That m is constant, at least to 1e-14, has been demonstrated inertially.
Therefore, units from the group "weight" are understood to be units of mass.
Re:Gravities? (Score:2)
Re:Gravities? (Score:2)
I meant in comparison to the other forces in the universe (electromagnetic, strong nuclear force, weak nuclear force and trek technobabble).
--
Evan (no reference worth guessing)
Re:Gravities? (Score:2)
Re:energy? (Score:2)
Yes. Thus I said (paraphrasing) 'I understand what they are trying to convey'... not that I thought it made scientific sense. It could be interpreted to mean many different specific things.
--
Evan
Re:energy? (Score:2)
The watt is not a unit of energy - it is a unit of power (i.e. how much energy per unit time). The unit of energy (in SI) is the Joule.
So if you dropped a 1kg weight 1 meter, 1 watt of energy would be used up.
No - it would be converted from gravitational potential energy to kinetic energy (and it would be 9.8J anyway). You don't use up energy per se (although you do (almost invariably) convert it from useful forms to less useful forms - this is entropy exerting its grip).
Gravity is not a type of mesurement. (Score:2)
Re:Gravity is not a type of mesurement. (Score:2)
Chris Y Taylor
Re:Gravity is not a type of mesurement. (Score:2)
>PORNO FOR THE PEOPLE [autopr0n.com]
Yep... measurement theory people, if a p0rn webmaster tells you about length, don't argue with him. He probably knows a hell of a lot more than you do
Re:Gravity is not a type of mesurement. (Score:2)
Great for horney geeks (Score:1)
Anti-grav condom (Score:3, Funny)
Smoking Crack at Jane's (Score:3, Interesting)
If it can vaporize the target, it's also able to vaporize the weapon that's emitting the beam. Newton's Third Law of Motion [k12.il.us] hasn't been repealed as far as I know.
Incorrect interpretation (Score:2)
If the weapon sending the beam is enormous (say 100 times the size of the target), it can withstand the "equal and opposite" force generated by object it's acting on.
Furthermore, if it's in space, it might just be sent to a higher orbit around the earth.
Re:Incorrect interpretation (Score:3, Informative)
Orbital Sniper [happypenguin.org]
Make people little red stains from a few miles up.
Re:Incorrect interpretation (Score:2)
Probably this is solved if you fire an equally strong shot in the opposite direction (most likely not in the direction of earth). You might hit the moon or some other plantes on the way, but what the heck
whuh? (Score:5, Funny)
Yes, and while we're at it, lets assume that light is force, pressure is density, and that current is pizza.
from what I know, the devices work by reflecting (and, I guess in this case) amplifying earth's gravity.
No.. (Score:2)
Re:Smoking Crack at Jane's (Score:5, Insightful)
Don't be so quick to assume that this weapon is simply a pushing or pulling effect... it could be a symmetrical sheering force (part of the target is, say, pulled up, and part is pulled down, ripping it apart) or something similar.
How the hell they generate a gravity-like force, however, is completely beyond me. No problem with Newton though. Perhaps it's electromagnetic yet affects nonconductors?
(Also, if you did have a "poking" type weapon, it may be possible to couple the gravitational force to a plasma inside the weapon that will be accellerated out of the back, absorbing whatever momentum the attack generated).
DISCLAIMER: I am not a physicist (yet) but I'm studying to become one.
1000 g? Say 'bye bye earth as we know it'. (Score:2)
Think about radiating cancer. If you would use one beam, all the tissue 'in the line of fire' gets fried, so they use several beams that focus on one point. I can imagine the same thing for 'gravitational guns'.
That solves one problem. Now for an other.
1000 g. That is 1000 times the power of earth's gravitation. So how far stretches this gravitational field? The moon is influenced by the earths one g gravitation. And vice versa, we have tides because of the much weaker gravitation of the moon.
My guess is that if you generate a 1000 g gravitational field anywhere on earth, the earth probably will collapse or is torn apart.
Has anyone other or more theories on this?
Re:1000 g? Say 'bye bye earth as we know it'. (Score:2)
As soon as someone leaks info and tells me the DoD or Darpa or Area51 or George Bush (no wait
My theory: you are a moron. (Score:2)
Same to you (Score:2)
g-force isn't equal to 9.8 Newton
1g pulls with 9.8 newtons on 1 kg of mass.
even is you can generate 9800N with your car, you'll never be able to generate 1000g with it.
Re:My theory: you are a moron. (Score:2)
Hrm... (Score:2)
Re:1000 g? Say 'bye bye earth as we know it'. (Score:3, Insightful)
The important point you are overlooking is that this fictional weapon generates a gravity RAY not a gravity FIELD. Much the way a 60w laser would cut through most anything that the small focused beam hit, even a long way off but not effecting stuff right next to it, while a 60w lightbulb would warm up everything very close to it.
Re:Smoking Crack at Jane's (Score:1)
Re:Smoking Crack at Jane's (Score:2)
Re:Smoking Crack at Jane's (Score:3, Funny)
. . . wait, that's not right . .
-Peter
Re:Completely ignores... (Score:2)
hmm (Score:1)
Programmer killed in moronic advertising stunt involving gravitron ray beam
And then people can reply with 300 comments of:
It's a graviton beam you moron.
But that won't be enough to take my server down. Nothing can harm a linux box, especially at 256 kilobits/second!
heh (Score:1)
Why else is most of the state "goverment no-fly zone"?
Greetz Jase... whatever your nik is...
The games. (Score:4, Interesting)
Too bad, some of them looked like they'd be fun to waste away a few hours.
Tim
Re: (Score:1)
Re:The games. (Score:2)
Re:The games. (Score:2)
Re:The games. (Score:2, Informative)
Tim
Re:The games. (Score:2)
For a few years there, it was pretty much all Doom. A little side-tracking for Descent and Duke Nukem, but other than that, from about 93 to 96, I was 'Doomed', so to speak. My relationships were doomed. My pay raises were doomed. Going out with friends was doomed. Movies were doomed to not get any money from me. The only ones who weren't doomed were the hardware manufacturers. Everyone else... yeah, doomed.
Got it all out of my system. Haven't touched a first-person shooter in years. Of course, the little rugrat is turning 4 in a couple of weeks and he wants a new bike and a gaming system. Oh man, the wife's gonna hate us spending hours on the couch. Quality time, sweetie. Quality time.
Lets go Redhat (Score:5, Interesting)
Of all the stupid things Redhat has bought or funded over the last few years, why can't they step in and front some cash and open up blender. At least blender is useful and the investment to buy it is dirt cheap. Finally the community has pretty much proven that it will actively develop the project. Perhaps this can be part of a Linux's new MM distribution.
Could Jesus microwave a burrito so hot that he himself could not eat it? HS
Re:Lets go Redhat (Score:2)
I don't think that's good idea. I think Redhat would be better off making an 'artist' distro that comes with Gimp, Killustrator, and eventually a version of Gimp that works like After Effects. Basically, they'd make one big distro that has all the tools us 3D Arists need. If they do that, then they make Redhat far more enticing as a graphic-workstation platform. That would give Newtek more reason to port Lightwave (which kicks Blender's butt up and down the court) over to Linux.
That'd be a hell of a deal. "Buy Lightwave, get RedHat Artist's edition for only $100 more. No need to spend $500 each on Photoshop and After Effects, and no need to have a Windows license!"
Re:Lets go Redhat (Score:2)
Re:Lets go Redhat (Score:2)
because they don't need to - the fund has been going for just a few weeks, they are up to 68K right now, 100K is absolutely no problem. and hey, I just kicked in my $75, screw RedHat, we don't need them for this. :)
Re:Lets go Redhat (Score:2)
Perhaps if it was a bean and cheese burrito. Not even He could withstand the power of the hot cheese plasma.
Re:Lets go Redhat (Score:2)
This line of logical thinking actually can lead to either St. Anselm's "proof" of the existance of God or a "proof" of the non-existance of God. Actually, it either prooves nothing, or if you take those statements to be true, you can proove anything.
Basically,
1. For all x, G > x.
2. There exists some y such that y > G.
How do these two statements resolve? They don't. True equals false, black equals white, anything and everything becomes provably true and provably false at the same time. But this is high school logic bullshit. If you want to use math or logic to get people to believe in God, explain to them the Church-Turing thesis or that relationship between the roots of the Reimann Zeta function and quantum physics or discuss incomputable functions.
Before people flame me for believing in God, let it be known that I am an athiest. I know, however, that there is beauty and order in the universe. I have seen the proof in mathematics and physics and computer theory. I have an appreciation for beauty, and distaste for arrogance.
Re:Lets go Redhat (Score:2)
Re:Lets go Redhat (Score:2)
Re:Lets go Redhat (Score:2)
I cannot comment on Redhat's business goals, but it looks like they still have a few nickels left in the bank. Take a look on the right side where it says, "Total Cash (mrq) $102.5M" [yahoo.com]...
Re:Lets go Redhat (Score:2)
Physical properties of matter... (Score:1)
--
If you find yourself struggling with loneliness, you're not alone. And yet you are alone...
Re:Physical properties of matter... (Score:2)
Re:Physical properties of matter... (Score:2)
Disregarding the fact that you're wrong, the idea is still interesting. In todays world, however, negative mass would somehow find its way into fastfood so that the dangerously obese would weigh a scant 10 kg or so. Hell, some of them would take off after a particularly large meal - new reason to sue McDonalds, perhaps?
"I swear, your Honor, I just had 6 BigMacs with fries and when I left the joint, I took off and was subjected to a traumatic view of the inner city - I demand compensation!".
HOWTO: move a planetoid (Score:2)
Bad Q! (Score:2)
Funny stuff... (Score:2, Interesting)
Tractators! Tractators! [google.com]
Re:Funny stuff... (Score:2)
Chris Y. Taylor
(related) Hindustan Times advertising (Score:2)
It would seem that the Indian Internet is already partially, if indirectly, funded from international sources.
Re:(related) Hindustan Times advertising (Score:2)
Still the ads wouldn't be there without US companies paying for them, which brings me back to my point: they're already getting money from us.
Boeing can afford it (Score:2)
shameless gravitics plug (Score:3, Interesting)
GRASP is not a codename for a current project but rather an acronym for a presentation entitled "Gravity Research for Advanced Space Propulsion," in which a Boeing engineer explains Podkletnov's theory and proposes that we should continue to monitor this work and perhaps even conduct some low-cost experiments.
I suspect that this internal Boeing presentation was the result of my presenation of a paper by Dr. Modanese and myself entitled "EVALUATION OF AN IMPULSE GRAVITY GENERATOR BASED BEAMED PROPULSION CONCEPT" (http://www.gravity-society.org/abstract_AIAA.htm
scientific study" that may have contribued to Boeing's internal GRASP presentation. I don't know where you can get a copy of the ESA's study.
Chris Y Taylor
Re:shameless gravitics plug (Score:2)
If any such papers actually lead to a functioning propulsion system, of course, they then become "breakthrough propulsion physics".
Chris Y Taylor
Whoa!! I own Boeing stock!! (Score:4, Funny)
"Boeing" and "Fraud" together in the headline. Especially these days...sheesh...
Martian Successor Nadesico (Score:2)
HOLY SHIT.
Anyone here seen the anime "Martian Successor Nadesico?" I can just see it now "GRAVITY BLAST IKIMASU!!!"
As quoted from: http://omoikane.cyril.com/comp/dict.html [cyril.com] Maybe anime is a few years ahead of science? Maybe we'll be jacking cables into our heads and connecting with our computers?
Corporate Partnerships for Blender? (Score:3, Interesting)
Anyway, one trend here in Los Angeles that has been rather popular is sponsorships by retail establishments. A public, listener-supported radio station in Santa Monica called KCRW gives members a "Membership Benefits" card. Coffee shops, record stores, book stores, resturants, and other types of stores give discounts (usually 10% off) to card-carrying KCRW subscribers. The "KCRW Membership Benefits card" is the incentive and/or justification for people to send in money.
Basically, this idea might work to help raise money for Blender. If an online shop such as ThinkGeek.com were to offer Blender subscribers 10% off any merchandise for one year, many more people would join. ThinkGeek.com would gain customers and free advertising. It would be a win-win situation for both the subscribers and the stores in question. If other online vendors were to offer discounts or other incentives, donating money to Blender would make even more sense. It is not inconceivable that with enough sponsors, a $50 subscription could pay for itself in discounts offered by sponsoring companies.
What the heck... (Score:2)
Re:What the heck... (Score:2)
The American Heritage lists the words as "regional," which may be a polite way to call it slang. It doesn't say which "region," but it's probably American. I know it's used here in the Southeast.
Re:The editors are morons! (Score:1, Offtopic)
Re:777 (Score:1)
oh, did i forget to mention engineering (all modern iterations)
Re:777 (Score:2, Interesting)
I was absolutely dumbfounded by this single fly- by - quick, fairly silent (due to the Very-high Bypass Engines) and gracefull...until the pilot pushed the twin-throttles forward to the stops and pulled back on the yoke - I swear it looked like the plane virtually LEAPED into the sky. Everyone around cheered, whooped, yelled and screamed with elation when that beautiful, white plane roared skyward!
The only word I can gather to describe that sight (and sound) is "Breathtaking"!
I received an email from a family member shortly after the attacks on 9/11 which had a JPEG attached to it, with several pictures of various military hardware in the JPEG, and a single caption:
"Mr. Osama Bin Laden: Now that you have acquainted yourself with some of our fine aircraft, please allow us to acquaint you with our other products"
The pictures were of a B-1B, a B-2, F-14 F-15, F-16, FA-18, Cruise Missles, etc.
ScottKin
bin laden jpg. (Score:2)
Re:Acceleration, etc. (Score:2)
Chris Y. Taylor
http://www.gravity-society.org/abstract_A
Re:Acceleration, etc. (Score:3, Insightful)
No, I don't mean you are a jerk, well you might be, but anyway, the measure of acceleration of acceleration is called "jerk".
Basically it is a measure of the rate of change of acceleration.
Position->Velocity->Acceleration->Jerk
Velocity is the measure of the rate of change of position.
Acceleration is a measure of the rate of change of velocity.
Jerk is the measure of the rate of change of acceleration.
Anyway, the jerk is what would be doing the destroying, so something that has a high velocity would probably be easier to destroy in theory, especially if it is moving away from you at the high velocity.
I think the idea is that you don't want to suddenly accelerate things toward you, that would sort of suck, but if they are already moving away from you, you can bring them to a rest destructively without shelling your gravity ray gun with pieces of the target.
As someone else said, this thing would be pretty likely to destroy itself anyway, but I think if it had enough mass in relation to the target, it could happen.
And all this is assuming you could even build this gravity ray, which is likely junk science at this point in time.
Re:Acceleration, etc. (Score:2)
I think that would literally suck. Dr. Podklentov reports, however, that his impulse gravity generator "pushes" on objects not "pulls." You don't have to worry about pulling debris into the emitter.
Also, it is reported to penetrate bulk matter and act on all types of matter with the same acceleration (just like gravity, hence the "gravity" in impulse gravity generator). The portion of the object in the beam path would experience NO internal stresses from that, just like an object in freefall may be accellerating rapidly, but because every part of it is accelerating the same there are no internal stresses. What might get destructive is where you have only a portion of the target in the beam, causing high internal stesses at that intersection. The portion in the beam undergoes high accleration, and the rest of the target does not; the beam takes a "core sample" out of any delicate components of the target in beam path. This is actually something you want to be careful to avoid when using the beam for propulsion. Current technology is so inefficient right now (and might have pointing accuracy limitations), however, that a gravitic ray is not likely to replace more conventional weapons in the near future.
Chris Y Taylor
http://www.gravity-society.org/abstract_A
Re:Acceleration, etc. (Score:2)
I would like you to imagine a body in free space. Any accelleration of that body, or any change in that accelleration (and so on), provided the change was uniform throughout the body. This is the norm for graviational forces with extremely small gradients, like that a tthe surface of the earth). In fact, uniform accellerations cannot possibly inflict damage on an object. There is no truth to the idea that "jerk" is what causes damage.
What causes damage to any object is the application of differing amount of force to different parts of the object. For instance, if I was to hit you with a baseball bat, I'd be applying a lot of force to a small area of your body (that is, the outer layer of your skin at the point of impact). The rest of your body would not feel this force, and thus part of you would be compressed. If I was to, say, apply the same amount of force evenly over your body, it would do you no harm whatsoever (in fact, you could not possibly detect it, unless you noticed you were suddenly moving relative to everything nearby, that is, assuming things are in fact nearby).
"Jerk" has nothing to do with it. The only way a gravity weapon can be harmful to something is for it to have a very strong gradient, or for you to change the path of the body in such a way that it causes a high speed collision.
See my other post [slashdot.org] about possible ways the device could inflict damage on something else without inflicting damage on itself. It's quite possible to destroy an object without applying a *NET* force to it.
Of course, we do not even fully understand what gravity "is", so it's somewhat rediculous to think that they are developing gravity based weapons any time soon. They did say "gravity-like" though, so who knows what that means...
DISCLAIMER: I am not a physicist, but I am studying to become one at Cornell.
Re:Acceleration, etc. (Score:2)
Re:Acceleration, etc. (Score:2)
Re:Acceleration, etc. (Score:3, Informative)
> Certainly they can. Take a familiar object (say, an empty soda can) and put it in a uniform 20g field and it would crush.
It would only crush if it was being pushed by the gravitational field against something else. And, if that is true, then obviously the bottom of the can is not being accellerated at all (it is staying in the same place). From the can's perspective, part of it (the top part) is being accellerated, while the bottom is not. That's not a uniform accelleration. The reason that objects can be crushed is that you can accellerate part of the object without accellerating the rest of the object, thus changing the size of said object!
Be careful that you are not confusing uniform acceleration with uniform velocity. The first is not an inertial reference frame while the second is. Any simple accelerometer will tell you that you are accelerating; it is the special relativity constancy of physics that holds in the intertial reference frame. You might be thinking of Einstein's Equivalence Principle that says (colloquially) that you can't tell if you are standing on the surface of the Earth or in an elevator that accelerates in free space at 9.8 m/s2.
Once again, you are wrong. A simple accelerometer only tells you if you are applying a force on the sensor element in the accellerometer. Imagine that you are in free space with no forces acting on you. A properly calibrated accellerometer will read zero. Then imagine that you are moving with some velocity, and you encounter a planet. You begin to be pulled towards the planet, but your accellerometer reads zero. It will only register a gravitational pull on the sensor element if there is something to oppose it. In this case, you have nowhere to stand, so you cannot oppose the gravitational force; thus it reads nothing. It is physically impossible for the accelerometer to "know" you are falling down the gravity well. Another way of saying it is that accelerometers only work if you are feeling a force that the sensing element is not. (for instance, you're being pulled by a drag line to a spaceship)
So while it is true that there is a big difference here between constant acceleration and constant velocity, it doesn't change the validity of my previous post. And inertial reference frames have nothing to do with this, my discussion is entirely in newtonian mechanics, it need not require relativity.
I suppose I understand how my points could have been misunderstood, as I use my words in a very precise manner. They will not be true when interpreted imprecisely.
Re:Acceleration, etc. (Score:2)
Simply put, accelerometers tell you if you are accelerating and it says nothing about applying different forces to particular sensor elements and not others. Consider the simplest of accelerometers: a flashlight. Shine a flashlight across a room and the beam travels a straight line. Now constantly accelerate the room and the beam "falls." No moving parts. This is a very nice Newtonian argument that you can find all over the place (such as here [astronomynotes.com]). If you invoke the Equivalence Principle, then this says that your flashlight beam will bend when you are in the constant accelerating field of the Earth. This is a nice General Relativity argument which you will find in pretty much all GR books (it will be referred to as the Einstein Elevator).
Rotation is something else that is very easy to detect, even if you are out in free space with no points of reference (such as a star field). Simply hold a ring laser gyro. This whole device relys on the Sagnac Effect which will tell you whether you are rotating (i.e., accelerating) or not. Rotation is just as easy to detect because it is involves acceleration.
As an aside, inertial reference frames do not depend on special relativity (SR), it is SR that depends on interial reference frames (this is the first of Einstein's three postulates). In the context of this discussion intertial reference frames have everything to do with it, and it doesn't mean we have to be talking about SR when we talk about inertial reference frames. The whole point of my previous post is that you can always tell that you are accelerating even if you are falling in the potential well of a planet or any other scenario you can dream up. Just use your flashlight (a finite speed of light is a wonderful thing, even in the Newtonian world). If you want to live only in a Newtonian world and you don't have a flashlight, then perform some intro physics conservation of momentum experiments on those noisy airtracks to see that you are not conserving momentum in your uniformly accelerating reference frame you say you cannot detect.
You also need to be careful about associating acceleration with motion. The can in the previous example does not crush because the bottom of the can is not accelerating while the top does, the whole can is accelerating (and uniformly (20g), I might add). Right now you are accelerating in your chair, but you don't move because the Earth is pushing back on you, but that doesn't mean you aren't accelerating. Remember, your weight is a force, and the force is proportional to your acceleration; no acceleration, no force holding you to your chair, and you would fly away.
Re:Acceleration, etc. (Score:2)
Yes, alas, I'm a Physicist In Training, so I tend to use such terms rather litterally. When I speak of force, I speak of it as a vector quantity, thus a uniform force could really only be in one direction. When I say uniform, I mean applied to the entire body, not simply to the surface as one would apply a force with, say, an earth-like atmosphere.
You raise a good point, I should be more careful to specify what I mean by things... I talk to physics majors so often that I take it ofr granted that everyone knows a "uniform force upon a body" means throughout the body inside and out. Clearly you've shown that's not the standard way of perceiving it.
Cheers,
Justin
Re:Acceleration, etc. (Score:2)
It's odd, most of the forces we encounter in our daily life are contact forces, so we're not intuitively used to the idea of a permeating force (like gravity).
But just to be a smart ass, I'll show that jerk is once again not responsible for the damage, no matter if it's being pulled on the surface or what.
I want you to imagine a body in free space, no forces acting on it. Now, say you have a drag line or something connected to it, from which you can pull on the object. This drag line is connected to the surface of the object, so, your force only acts on the object.
Now, to make things more obvious, lets say the object is a long chain of various modules... you're only pulling on the first, and the chains holding them all together pull on the rest. In reality, any structure is a lot like that on a very small level, so it seems appropriate enough to me. Lets say that you use a rocket to apply a near-constant acceleration pulling this thing. I say near constant, because its thrust slowly increases.
As this thrust slowly increases, so does the force on the first module. And anyone that's done a bit of mechanics will know this also increases the force on the next module, and so on. Chains have a finite strength. Continue to keep upping the trust and you will reach a point at which the object breakds because the chains holding it together can no longer take this constant force.
Anyways... why isn't JERK the problem? Well, it comes from the fact that the thing that deforms an object is a force, not a change in force. If you took a can and suddenly applied 500+ lbs of force to the top of it, sure it'd crumple but the same thing gos if you slowly stacked up weights on top. There are exceptions to this rule (namely certain materials are affected by the shock waves created by large change in force at their surface) or that have structural properties that change over time (for instance, oobleck, that gooie cornstarch stuff that gets hard if you smack it). This is a valid point, however this is a specific phenomenon related to a specific set of materials, and is not a general physical principle. I suppose it could be argued that if you had a gravity weapon like that, that to save power, you'd pulse it such that the force wasn't enough to destroy the object but that it was quick enough to send a shockwave through the object to destroy delecate internals.
Is that what you meant?
Re:Acceleration, etc. (Score:2)
rate of change of Snap is called Crackle.
rate of change of Crackle is called... can you guess it...
Pop.
I don't know what they are beyond that.
Chris Y Taylor
Re:Acceleration, etc. (Score:2)
Look if you have to worry about the derivetive of jerk being positive, it most likey will come ov.
Re:incoherent (Score:3, Interesting)
It is also quite common to use scalar numbers when direction is implied by context, so lowercase g is certainly not always a vector.
So who are you complaining about?
Re:incoherent (Score:2)
I guess your point is correct that they should use (lower case) g, but it's clear enough when used in the right context what 'G' means.
Re:Just a simple question of 1st grade physics (Score:2)
Ludicrous Speed involves cartoon animals.
Breakneck Speed requires a neck to break.
Therefore, a cartoon animal will outrun a fish, but not if it's a cartoon fish. Given that you can safely assume that Ludicrous Speed easily is faster than Breakneck Speed (as Breaking The Neck of the Speeder should pretty much end the speeding). If you are a cartoon animal you cannot permanently break your neck so therefore you can exceed Breakneck Speeds.