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#4805

theism (07/30/2015) []
Is it possible that light doesn't have the maximum velocity of anything but rather the maximum momentum?
#4813 to #4805

subtard (15 hours ago) []
E^2 = (pc)^2 + (mc^2)^2
The (pc)^2 term only ever matters when approaching the speed of light, which is makes the rest boil down to E=mc^2 where m=mass at rest. However photons have no mass at rest which means E = pc. P comes from relativistic momentum which is equal to Planck's constant divided by the light's wavelength. The average visible light has somewhere around 10^27 kg*m/s momentum from this.
Compare that to some example values from this site www.batesville.k12.in.us/physics/PhyNet/Mechanics/Relativity/relativistic_momentum.html to show that light really has negligible momentum.
The (pc)^2 term only ever matters when approaching the speed of light, which is makes the rest boil down to E=mc^2 where m=mass at rest. However photons have no mass at rest which means E = pc. P comes from relativistic momentum which is equal to Planck's constant divided by the light's wavelength. The average visible light has somewhere around 10^27 kg*m/s momentum from this.
Compare that to some example values from this site www.batesville.k12.in.us/physics/PhyNet/Mechanics/Relativity/relativistic_momentum.html to show that light really has negligible momentum.
#4808 to #4805

anon (18 hours ago) []
Light has velocity because it is not a solid matter. Light is light, simply put, and it cannot gain or lose momentum. Indeed it has no momentum. The velocity at which rays of light move is affected only by the environment in which it moves. Although it can be manipulated to move slower or faster through certain factors and variables, light has no momentum.
#4803

theism (07/28/2015) []
What environmental conditions would reduce the fire activity of a high oxygen atmosphere? The best I can think of is atmospheric moisture,
#4810 to #4807

anon (18 hours ago) []
Exactly. High pressure would cause a reaction to be more volatile in most scenarios. There's a few simple things that affect the behavior of a chemical reaction. 1. Agitation (e.g. in a liquid mixture, stirring it faster to help disolve/mix, or when you push around hot coals in a dying fire to start the flames again) 2. Pressure (as mentioned) and 3. Temperature.
#4800

theism (07/25/2015) []
What does a trex even do with it's arms? They aren't much use for claws or manipulation so whats the point?
#4794

luigipimp (07/20/2015) []
i heard if time stopped, that you would be burned up by the friction of air molecules but wouldnt that mean you wouldnt be able to breathe since the air would stop flowing and not be able to move since the air molecules wouldnt move out of the way from displacement?
#4787

ravenpt (07/18/2015) []
Hey. I need a little help with some hypothesis test that myself and a teacher of mine at uni disagree at. So here it goes:
A school director wants to start classes at saturday, but he will only do so if 80% of the students are willing to attend. With a degree of confidence of 95%, should the director start the classes at saturday?
Students that said they will attend: 288 of 400 (wich will make 0.72)
So I said that the director shouldn't start them because:
H0: p<=0.8 (The data indicates that there won't be enough students)
H1: p>0.8 (The data indicates that at least 80% of students will attend)
Since the outcome will be negative (0.720.8=0.08) there is no chance the result can be positive, so H0 is accepted.
While she did the following:
H0: p=>0.8 (Students will attend the class)
H1: p < 0.8 (Students will not attend the class)
And in this one, H0 is also passed. But this last test only demonstrates that there isn't 95% of certainty that less than 80% will attend the class right? Am I going nuts?
A school director wants to start classes at saturday, but he will only do so if 80% of the students are willing to attend. With a degree of confidence of 95%, should the director start the classes at saturday?
Students that said they will attend: 288 of 400 (wich will make 0.72)
So I said that the director shouldn't start them because:
H0: p<=0.8 (The data indicates that there won't be enough students)
H1: p>0.8 (The data indicates that at least 80% of students will attend)
Since the outcome will be negative (0.720.8=0.08) there is no chance the result can be positive, so H0 is accepted.
While she did the following:
H0: p=>0.8 (Students will attend the class)
H1: p < 0.8 (Students will not attend the class)
And in this one, H0 is also passed. But this last test only demonstrates that there isn't 95% of certainty that less than 80% will attend the class right? Am I going nuts?
#4792 to #4787

smudgiemuffins (07/19/2015) []
Quick note, null hypotheses cannot be set up like x<=n. They must be in the form x=n. The only valid operator for a null hypothesis is an equal sign. Also, your alternative hypothesis should be testing for whether or not p is actually lower than 0.8.
Your phrasing of the question was a tad ambiguous. Is the intent that the teacher has exactly 400 students, and 288 said they will definitely comes? That doesn't imply that the other 112 wont. Nor can we make a statement about them because the 288 who did answer do not in any way represent the 112 who didn't. If I were talking about this on a statistics test, I'd call it "response bias" to please the teacher and just say this is a bad survey.
Now, if the teacher has, say, ~4000 students and 400 random students responded. 288 said yes, 112 said no. Then it's quite easy. You've got a large, random sample thus the central limit theorem holds and zprocedures are valid. This yields a confidence interval of (.676, .764) at 95% confidence. Or in colloquial terms, we're pretty damn sure there are not a proportion of .8 students going to attend.
Or, what is in my opinion the better way to approach this test but less intuitive depending on what kind of stats class you're taking. A 95% percent confidence interval implies a level of significance at 5%. A 1proportion ztest yields a pvalue(not proportion, just to be clear) of 3.17*(10^5). Meaning, by the level of significance and really any reasonable level of significance the H0 that p=0.8 should be rejected.
Your phrasing of the question was a tad ambiguous. Is the intent that the teacher has exactly 400 students, and 288 said they will definitely comes? That doesn't imply that the other 112 wont. Nor can we make a statement about them because the 288 who did answer do not in any way represent the 112 who didn't. If I were talking about this on a statistics test, I'd call it "response bias" to please the teacher and just say this is a bad survey.
Now, if the teacher has, say, ~4000 students and 400 random students responded. 288 said yes, 112 said no. Then it's quite easy. You've got a large, random sample thus the central limit theorem holds and zprocedures are valid. This yields a confidence interval of (.676, .764) at 95% confidence. Or in colloquial terms, we're pretty damn sure there are not a proportion of .8 students going to attend.
Or, what is in my opinion the better way to approach this test but less intuitive depending on what kind of stats class you're taking. A 95% percent confidence interval implies a level of significance at 5%. A 1proportion ztest yields a pvalue(not proportion, just to be clear) of 3.17*(10^5). Meaning, by the level of significance and really any reasonable level of significance the H0 that p=0.8 should be rejected.
#4771

aliennova (07/16/2015) []
I recently came up with a hypothesis about gravity. I have a lot of problems with our current theory on gravity as the only thing it explains is the more mass something has, the more gravity it has. Nothing else What if gravity is just another dimension? Of course I ran into the problem "Well, then what force pushes/pulls objects in that dimension if not gravity?"
This is really hard to explain so I'm going to start a comment chain. This is just something I thought of, and I do not believe it to be correct. I would love to hear all your hypothesis on what gravity exactly is!
This is really hard to explain so I'm going to start a comment chain. This is just something I thought of, and I do not believe it to be correct. I would love to hear all your hypothesis on what gravity exactly is!
#4793 to #4771

smudgiemuffins (07/19/2015) []
I'm quite confused as to what you're trying to get at. Dimensions are useful mathematical objects meant to describe objects with a quality of, for lack of a better word, independence. Take the classical physics example. If you drop a ball and throw a ball sideways, they still and at the same time. The ball's xcomponent velocities have nothing to do with their y's. And this conflates dimensions as things they can only refer to space and time. Consider a function like f(x,y) = xy. X and Y can both be thought of as dimensions of function f.
I like the informal definition of dimensions wikipedia gives. It's the least number of coordinates to specify any point within it. Take the function f I said earlier, you require two numbers to specify any value f can take.
There is where it is useful to differentiate kinematics and dynamics. I'll loosely say discussion of dimension in this way is more in the realm of kinematics, which is the study of motion without consideration of the causes. I say this because the definition of a space within which there are dimensions simply defines a set which some function can take. Gravity, a consideration in dynamics, more describes the cause of force. It isn't itself a motion but rather a cause of motion.
I feel like I can be a bit more concise if you'll allow a more mathematical view. When we say dimensions(the spatial ones and time) we usually mean something like a function like f(x,y,z,t) where f defines some physical quantity with relationship the standard "motion dimensions." Either f or one of it's derivatives is what describes something like gravity, a cause or description of the cause of motion rather than a dimension of motion itself. Things like mass or charge often scale functions like f but can also be functions themselves.
I like the informal definition of dimensions wikipedia gives. It's the least number of coordinates to specify any point within it. Take the function f I said earlier, you require two numbers to specify any value f can take.
There is where it is useful to differentiate kinematics and dynamics. I'll loosely say discussion of dimension in this way is more in the realm of kinematics, which is the study of motion without consideration of the causes. I say this because the definition of a space within which there are dimensions simply defines a set which some function can take. Gravity, a consideration in dynamics, more describes the cause of force. It isn't itself a motion but rather a cause of motion.
I feel like I can be a bit more concise if you'll allow a more mathematical view. When we say dimensions(the spatial ones and time) we usually mean something like a function like f(x,y,z,t) where f defines some physical quantity with relationship the standard "motion dimensions." Either f or one of it's derivatives is what describes something like gravity, a cause or description of the cause of motion rather than a dimension of motion itself. Things like mass or charge often scale functions like f but can also be functions themselves.
#4779 to #4771

nought (07/17/2015) []
string theory actually hypothesizes gravity as a result of strings in more dimensions, but not a dimension itself. Gravity is a consequence of the geometry of 4D spacetime. Unofrtunately, your hypothesis has no evidence, while there is evidence that gravity is the warping of spacetime
#4772 to #4771

aliennova (07/16/2015) []
Okay so before I start, I should explain how I imagine extra dimensions.
You obviously can't imagine/perceive a spacial I say spacial because I have another personal hypothesis that time is something like another dimension, I might explain this one later. dimension. So Instead I imagine that the world is flat, 2 dimensional, but I'm still able to perceive the third dimension. Paint skills novice
You obviously can't imagine/perceive a spacial I say spacial because I have another personal hypothesis that time is something like another dimension, I might explain this one later. dimension. So Instead I imagine that the world is flat, 2 dimensional, but I'm still able to perceive the third dimension. Paint skills novice
#4777 to #4774

Zaxplab (07/16/2015) []
But... The first dimension is a point. Nothing else. Just an infinitely small, almost indefinable point. The second dimension consists of infinite points, formed together to create planes. The third dimension is infinite amounts of planes, which creates.... dimension.
I think the third dimension would be Time to the second dimension, just as the fourth dimension is Time to us.
I think the third dimension would be Time to the second dimension, just as the fourth dimension is Time to us.
#4769

luigipimp (07/15/2015) []
could walking around a lot all day from work make kind of a soft bump in between my big and second toe and be achey. looks kind of like a vein without the blue
#4764

lilliliililililill (07/11/2015) []
should i activate java on
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#4762

luigipimp (07/11/2015) []
how can primitive tools build all those ancient stone things if it would take a lot of time to build them with modern technology
#4766 to #4762

rainbowrush ONLINE (07/13/2015) []
They brought the rocks using the river for fast transport then simply paid people to roll them up.
I am unsure how they lifted the rocks weighing more than a ton, though. I suspect they used sand or some sort of crane mechanic.
I am unsure how they lifted the rocks weighing more than a ton, though. I suspect they used sand or some sort of crane mechanic.
#4744

entarasu ONLINE (07/10/2015) []
you are my last hope guys pls can you help me with this shitty problem
Let A and B two components of a binary system whose neidealitate liquid phase is characterized by the equation
Scatchard Hildebrandt:
GE = KxAxB where K = 5820J / mol
It is a constant independent of temperature. An amount of 7 mol of component B is added slowly under continuous stirring, over 1 mol of component A, both at the temperature T0. Determine the minimum temperature value T0 which remains singlephase multisystem throughout the experiment. Heat capacity of componenÎ¼ilor are
CP, CP A = B = 30J / mol K
And, under experimental conditions, heat exchanges between
system and the external environment can neglected
Let A and B two components of a binary system whose neidealitate liquid phase is characterized by the equation
Scatchard Hildebrandt:
GE = KxAxB where K = 5820J / mol
It is a constant independent of temperature. An amount of 7 mol of component B is added slowly under continuous stirring, over 1 mol of component A, both at the temperature T0. Determine the minimum temperature value T0 which remains singlephase multisystem throughout the experiment. Heat capacity of componenÎ¼ilor are
CP, CP A = B = 30J / mol K
And, under experimental conditions, heat exchanges between
system and the external environment can neglected
#4763 to #4744

zonetransferrer (07/11/2015) []
write it down to paper and post a photo of it. it is easier to read and write than describing it in word processor.
#4743

rainbowrush ONLINE (07/10/2015) []
If there are infinite realities, why haven't a different me found a way to cross from reality to reality to give me a pink yoyo?
Does time exist other than a form of measurement; does the past and future exist other than words to describe what was and what will be?
Does time exist other than a form of measurement; does the past and future exist other than words to describe what was and what will be?
#4790 to #4743

djequalizee (07/19/2015) []
infinite realities =/= infinite different realities. They could all be the exact same
#4768 to #4743

supahsayin (07/15/2015) []
If there are infinite realities, you just might be in one that ends up not having anyone cross dimensions while you're alive.
#4740

alltimetens (07/09/2015) []
I keep trying to explain to my friend that astral projections and the psychic staring effect are not real.
What can I do to convince her?
What can I do to convince her?
#4770 to #4736

dotheherpaderp ONLINE (07/16/2015) []
Getting chickenpox as a child doesn't make you immune to it for life. In fact, it'll make you more susceptible to shingles in adulthood.
This is why doing those "chickenpox parties" to get one's kids deliberately infected has not been and is still not a good idea. A vaccine already exists.
This is why doing those "chickenpox parties" to get one's kids deliberately infected has not been and is still not a good idea. A vaccine already exists.
#4741 to #4739

raeptiemx (07/09/2015) []
did you know that um if you don't get Vit K you can bleed to death?
That's because Vit K is responsible for adding glutamate to various clotting factors without which they'd suck dick and you'd die from any kind of cut(
Hand over 30 bucks now or I'll shoot you with some heparin and then stab you.
You'll bleed faster than my average sex time with my wife
That's because Vit K is responsible for adding glutamate to various clotting factors without which they'd suck dick and you'd die from any kind of cut(
Hand over 30 bucks now or I'll shoot you with some heparin and then stab you.
You'll bleed faster than my average sex time with my wife
#4732

pokemonstheshiz (07/07/2015) []
Assuming multiple dimensions exist and it is possible to traverse between them, what methods would you first use to try and get there?
#4734 to #4733

pokemonstheshiz (07/07/2015) []
I think provided a wormhole can be traveled through, finding or creating an instance where two wormholes intersect might be a good bet
#4735 to #4734

sugoi ONLINE (07/07/2015) []
Yeah that's what the antimatter and black hole was for.
Antimatter hopefully tears the universe apart making a worm hole or a black hole could potentially already be a worm hole.
Either way I am no science man and most likely a complete retard in regards to this subject.
Antimatter hopefully tears the universe apart making a worm hole or a black hole could potentially already be a worm hole.
Either way I am no science man and most likely a complete retard in regards to this subject.
#4728

zonetransferrer (07/06/2015) []
can anyone help me with this?
From mountain lake, which surface lies 100m above hydroelectric plant, is going to have new metal pipeline 1900m in a way that overpressure at plant has to be atleast 0.588 MPa and volume of water flowing to be 4 m^3/min. What diameter should pipeline have, assuming that equivalent lenght of pipeline with local resistances is equal to 10% of real lenght of pipeline. T= 10Â°C. abrasiveness is 0.2mm
mostly i am interested in how unit conversion in step 1 worked to end up m^2/s^2
for step 4 i am going to add another comment
From mountain lake, which surface lies 100m above hydroelectric plant, is going to have new metal pipeline 1900m in a way that overpressure at plant has to be atleast 0.588 MPa and volume of water flowing to be 4 m^3/min. What diameter should pipeline have, assuming that equivalent lenght of pipeline with local resistances is equal to 10% of real lenght of pipeline. T= 10Â°C. abrasiveness is 0.2mm
mostly i am interested in how unit conversion in step 1 worked to end up m^2/s^2
for step 4 i am going to add another comment
#4742 to #4738

zonetransferrer (07/09/2015) []
process Engineering 1, part of it is about bilantion , fluid dynamics (more like fluid flow in pipelines), and another is about transferring heat.
#4727

zonetransferrer (07/06/2015) []
hypotetical situation.
you are in a room with perfect blank white walls there is just you and you have 10g of maryjane. how would you got high from it? you have absolutely nothing but the grass, room is empty, there is light in the room but no light source,( just assume that there is light.)
I already tough of stuffing it up my ass and let colon to absorb it. any ideas?
you are in a room with perfect blank white walls there is just you and you have 10g of maryjane. how would you got high from it? you have absolutely nothing but the grass, room is empty, there is light in the room but no light source,( just assume that there is light.)
I already tough of stuffing it up my ass and let colon to absorb it. any ideas?