It's been a while since I've messed with stuff like this, but
this part: exp[(-1/2(x-alpha)'(sigma2V)-1(x-alpha)
suggests that this does have something to do with a multivariate normal distribution.
The missing brackets and parentheses look like typos.
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suggests that this does have something to do with a multivariate normal distribution.
Huh, yeah, as initially suspected.
The missing brackets and parentheses look like typos.
Oh, golly.
Cheers.
Addendum: For kicks, if anyone wants to read the paper, the citation is Venditti C., Meade A., Pagel M. (2011.) Multiple routes to mammalian diversity, Nature, 479(7373):393–396. A short and skinny? The article is rather euh and, truthfully, there science is less than what I expect from an article in Nature. Abandon hope all ye who enter here.
Can anyone help me on what I did that was incorrect on this high school physics problem? Please note that since it's high school physics, it is algebra based.
The situation: A person drags a sled at constant speed across the snow with the angled force shown in the diagram attached. Determine the coefficient of friction between the sled and the ground.
So basically, I have to find μ. As part of the class, we were given the following equations to possibly use:
Ff = (μ)(Fn)
Ff = (Ff)(d)
Where Ff is the force of friction; μ is the coefficient of friction; Fn is the normal force; and d is the distance.
Anyways, here's the work I showed--
Such that
Fn = (mass)(gravity)
Fn = (90 kg)(9.8 m/s2)
Fn = 882 N
Since the object is moving at constant speed, there are no net forces acting on it.
Hence: Ffric = 200, 100+N = 90*9.8 -> N = 782.
From Ffric = mu*N, mu = 200/782 = 0.256.
Two things; how does τ differ from 2π? In undergraduate frosh maths, one of the profs. said that they were one and the same. Secondly, in short, for what reason is 2*pi 2*pi? I followed the articles that you've linked me to and may have gone astray.
Thanks, Einsteinmonkey.
the authors were sloppy with their parentheses.
The authors were sloppy with their science, experimental design, representation of data, analysis of results, and oh-so much.
I had never heard of it before, but it looks like tau and 2pi are indeed the same thing.
Also, 2pi is there because it's part of the pdf of a normal distribution.
Take a look at the pdf of a multivariate normal distribution and it should look familiar.
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Can someone explain (in simple terms) the difference between conduction, convection, and radiation?
Also, the difference between: internal energy, temperature, and heat.
For the first question, the cooking analogy is the easiest way to think about it for me. Imagine a steak cooking on a grill. There are three ways the steak is cooking:
Conduction: hot metal grates are transferring energy into the meat by direct contact.
Convection: hot air is rising up from the coals and surrounding the meat, transferring energy into it.
Radiation: heat waves (infrared radiation) are coming off of the glowing goals and bombarding the meat, transferring energy to to it.
Internal energy is the total energy contained within a system. The two components are: kinetic energy, which is the energy from "motion" (atoms and molecules vibrating and moving around, the object itself moving, etc.); and potential energy, which is the "stored" energy (static electricity before a spark, the energy in a chemical bond before it's broken, etc.). From an equation standpoint, you can calculate how the internal energy of a system changes by adding up the work done on the system and the heat added to the system.
Say you have a metal coffee can sitting still at room temperature. Its internal energy is X. If you push the can and it starts rolling, you do work on it, and it adds to the kinetic energy (because now it's in motion. Now its internal energy is X+Y. If you then hit it with a blowtorch, you heat up the metal, and it adds to the kinetic energy (because the molecules are vibrating more quickly). Now its internal energy is X+Y+Z.
Temperature is the result of the kinetic energy of the particles within something. As the molecules in an object vibrate more quickly, the temperature of that object rises. Temperature is an easy to measure proxy for (part of) the kinetic energy contained within an object.
Heat is "energy transferred in any way other than work" (Wikipedia). In other words, heat isn't a property of an object, but rather a process that occurs when there is a temperature difference between two objects. Heat transfer is the process by which two objects with difference temperatures arrive at the same temperature. Energy can be transferred as heat in a variety of ways: conduction, convection, radiation, etc.
For the first question, the cooking analogy is the easiest way to think about it for me. Imagine a steak cooking on a grill. There are three ways the steak is cooking:
Conduction: hot metal grates are transferring energy into the meat by direct contact.
Convection: hot air is rising up from the coals and surrounding the meat, transferring energy into it.
Radiation: heat waves (infrared radiation) are coming off of the glowing goals and bombarding the meat, transferring energy to to it.
So would it be wrong to say...
Conduction is heat transfer from solid to solid.
Convection is heat transfer from fluid to fluid by currents.
Radiation is heat transfer through space by waves. ?
I had never heard of it before, but it looks like tau and 2pi are indeed the same thing.
Thanks, I didn't know they were the same thing either.
Where do they write tau in the paper, though? The supplemental materials use 2*pi.
Also, 2pi is there because it's part of the pdf of a normal distribution.
Take a look at the pdf of a multivariate normal distribution and it should look familiar.
Convection is heat transfer from fluid to fluid by currents.
Radiation is heat transfer through space by waves. ?
Well, conduction can be from a fluid to a solid, like deep fat frying. Conduction always takes place by physical contact between two pieces of matter. Mixing hot and cold water operates by conduction. Conduction is the most "direct" form of heat transfer.
Convection requires some kind of bulk medium around the two objects that aren't touching each other. So heat transfers from the hot coals to the meat by traveling through the air, in simplified terms.
Another way to think about it is:
Conduction requires direct contact.
Convection requires a physical medium (air, water).
Radiation requires neither.
Well, conduction can be from a fluid to a solid, like deep fat frying. Conduction always takes place by physical contact between two pieces of matter. Mixing hot and cold water operates by conduction. Conduction is the most "direct" form of heat transfer.
Convection requires some kind of bulk medium around the two objects that aren't touching each other. So heat transfers from the hot coals to the meat by traveling through the air, in simplified terms.
Another way to think about it is:
Conduction requires direct contact.
Convection requires a physical medium (air, water).
Radiation requires neither.
Conduction is the transfer of heat energy via direct contact.
Convection is the transfer of heat energy by a physical medium such as air or water.
Radiation is the transfer of heat energy without direct contact or a physical medium via electromagnetic waves.?
Edit: I'm trying to word it in a way so my professor won't take off points. He's very nitpicky.
internal energy is all the kinetic and sometimes potential energy in an object
heat is the transfer of energy from one object to another
temperature is the average kinetic energy of an object, per volume, per size plus other considerations
internal energy is all the kinetic and sometimes potential energy in an object
heat is the transfer of energy from one object to another
temperature is the average kinetic energy of an object, per volume, per size plus other considerations
does this look right?
Internal energy is always both the kinetic and potential energy. Every object has potential energy; some have more than others.
Heat is the transfer of energy from one object to another without doing work. Or in simpler terms, without moving it. I can transfer energy to a soccer ball by kicking it; that's doing work on it, not heat transfer.
Internal energy is always both the kinetic and potential energy. Every object has potential energy; some have more than others.
Heat is the transfer of energy from one object to another without doing work. Or in simpler terms, without moving it. I can transfer energy to a soccer ball by kicking it; that's doing work on it, not heat transfer.
All of this should be taken with the caveat that I'm a chemist, not a physicist. I haven't taken physics in years, so my definition skills may be rusty
All of this should be taken with the caveat that I'm a chemist, not a physicist. I haven't taken physics in years, so my definition skills may be rusty
Well I plan on reading my definitions to him during office hours. So if the wording is somewhat off, he'll correct me.
Thanks for all the help! I'm officially unstressed about this quiz.
I had never heard of it before, but it looks like tau and 2pi are indeed the same thing.
Another day, another fact or factoid.
Also, 2pi is there because it's part of the pdf of a normal distribution.
Take a look at the pdf of a multivariate normal distribution and it should look familiar.
All righty.
The bottom line of this is that, as I can't solve the equation, don't need to program it, and my roots are technically in some other niche, I shouldn't be too fussed. Thank goodness.
Thanks, guys. I'll be sure to Wikipedia things (or as well) in the future.
The bottom line of this is that, as I can't solve the equation, don't need to program it, and my roots are technically in some other niche, I shouldn't be too fussed. Thank goodness.
Thanks, guys. I'll be sure to Wikipedia things (or as well) in the future.
I'm not certain what you mean by "solve the equation", but maximizing the log-likelihood gives you a closed form estimator, the GLS estimator. I'm not too familiar with incorporating Bayesian stats into that, but you should still be able to get an explicit result with a well-behaved prior.
That isn't so bad. You can make a few sentences with no "E's" fairly easily. Now, making it a readable, intelligent paper may be more difficult, but think of it this way- You need a title, and space under the title, which will already take some work off. Use your paragraphs, the tab before each one will also take off some of the work.
It can be on anything you want? Then try and find a pretty general topic, so you can say vague things, and essentially whatever you want. Otherwise, you get stuck.
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I need a to write a one page paper on anything using no "E's". Help?
Presumably meant to play off of this novel. The second section in that article (and possible more by following links) seems to have a couple of implicit pointers.
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But solutions can be roughly simulated on a computer with a massive number of calculations. If those terms are what I think those terms are.
this part: exp[(-1/2(x-alpha)'(sigma2V)-1(x-alpha)
suggests that this does have something to do with a multivariate normal distribution.
The missing brackets and parentheses look like typos.
EDH:
UBR Sedris, the Traitor King
BGW Karador, Ghost Chieftain
RG Radha, Heir to Keld
Oh, golly.
Cheers.
Addendum: For kicks, if anyone wants to read the paper, the citation is Venditti C., Meade A., Pagel M. (2011.) Multiple routes to mammalian diversity, Nature, 479(7373):393–396. A short and skinny? The article is rather euh and, truthfully, there science is less than what I expect from an article in Nature. Abandon hope all ye who enter here.
— jean-baptiste alphonse karr, les guêpes (1849)
wiki subforum @ mtgs forums * mtgs wiki * site rules
Assuming you have some background, that formula is the likelihood function (used in maximum likelihood estimation, a widely used method for estimating parameters) for generalized least squares (a generalization of ordinary least squares that allows for heteroskedasticity and serial correlation in the errors) with multivariate normal errors.
The situation: A person drags a sled at constant speed across the snow with the angled force shown in the diagram attached. Determine the coefficient of friction between the sled and the ground.
So basically, I have to find μ. As part of the class, we were given the following equations to possibly use:
Ff = (μ)(Fn)
Ff = (Ff)(d)
Where Ff is the force of friction; μ is the coefficient of friction; Fn is the normal force; and d is the distance.
Anyways, here's the work I showed--
Such that
Fn = (mass)(gravity)
Fn = (90 kg)(9.8 m/s2)
Fn = 882 N
And
Ff = -200 N {taken from the diagram}
So that
Ff = (μ)(Fn)
(-200 N) = (μ)(882 N)
Therefore
μ = -.226
Where did I mess up?
Downwards: 90*9.8
Right: 200
Left: Ffric.
Since the object is moving at constant speed, there are no net forces acting on it.
Hence: Ffric = 200, 100+N = 90*9.8 -> N = 782.
From Ffric = mu*N, mu = 200/782 = 0.256.
| Ad Nauseam
| Infect
Big Johnny.
Thanks, Einsteinmonkey.
The authors were sloppy with their science, experimental design, representation of data, analysis of results, and oh-so much.
— jean-baptiste alphonse karr, les guêpes (1849)
wiki subforum @ mtgs forums * mtgs wiki * site rules
Also, 2pi is there because it's part of the pdf of a normal distribution.
Take a look at the pdf of a multivariate normal distribution and it should look familiar.
EDH:
UBR Sedris, the Traitor King
BGW Karador, Ghost Chieftain
RG Radha, Heir to Keld
Can someone explain (in simple terms) the difference between conduction, convection, and radiation?
Also, the difference between: internal energy, temperature, and heat.
For the first question, the cooking analogy is the easiest way to think about it for me. Imagine a steak cooking on a grill. There are three ways the steak is cooking:
Internal energy is the total energy contained within a system. The two components are: kinetic energy, which is the energy from "motion" (atoms and molecules vibrating and moving around, the object itself moving, etc.); and potential energy, which is the "stored" energy (static electricity before a spark, the energy in a chemical bond before it's broken, etc.). From an equation standpoint, you can calculate how the internal energy of a system changes by adding up the work done on the system and the heat added to the system.
Say you have a metal coffee can sitting still at room temperature. Its internal energy is X. If you push the can and it starts rolling, you do work on it, and it adds to the kinetic energy (because now it's in motion. Now its internal energy is X+Y. If you then hit it with a blowtorch, you heat up the metal, and it adds to the kinetic energy (because the molecules are vibrating more quickly). Now its internal energy is X+Y+Z.
Temperature is the result of the kinetic energy of the particles within something. As the molecules in an object vibrate more quickly, the temperature of that object rises. Temperature is an easy to measure proxy for (part of) the kinetic energy contained within an object.
Heat is "energy transferred in any way other than work" (Wikipedia). In other words, heat isn't a property of an object, but rather a process that occurs when there is a temperature difference between two objects. Heat transfer is the process by which two objects with difference temperatures arrive at the same temperature. Energy can be transferred as heat in a variety of ways: conduction, convection, radiation, etc.
Conduction is heat transfer from solid to solid.
Convection is heat transfer from fluid to fluid by currents.
Radiation is heat transfer through space by waves. ?
Thanks, I didn't know they were the same thing either.
Where do they write tau in the paper, though? The supplemental materials use 2*pi.
Heh, the one term I neglect to link
Well, conduction can be from a fluid to a solid, like deep fat frying. Conduction always takes place by physical contact between two pieces of matter. Mixing hot and cold water operates by conduction. Conduction is the most "direct" form of heat transfer.
Convection requires some kind of bulk medium around the two objects that aren't touching each other. So heat transfers from the hot coals to the meat by traveling through the air, in simplified terms.
Another way to think about it is:
Conduction requires direct contact.
Convection requires a physical medium (air, water).
Radiation requires neither.
Conduction is the transfer of heat energy via direct contact.
Convection is the transfer of heat energy by a physical medium such as air or water.
Radiation is the transfer of heat energy without direct contact or a physical medium via electromagnetic waves.?
Edit: I'm trying to word it in a way so my professor won't take off points. He's very nitpicky.
Sounds good to me You should totally go with the steak analogy
heat is the transfer of energy from one object to another
temperature is the average kinetic energy of an object, per volume, per size plus other considerations
does this look right?
Internal energy is always both the kinetic and potential energy. Every object has potential energy; some have more than others.
Heat is the transfer of energy from one object to another without doing work. Or in simpler terms, without moving it. I can transfer energy to a soccer ball by kicking it; that's doing work on it, not heat transfer.
Okay. But my temperature definition is spot on?
All of this should be taken with the caveat that I'm a chemist, not a physicist. I haven't taken physics in years, so my definition skills may be rusty
Well I plan on reading my definitions to him during office hours. So if the wording is somewhat off, he'll correct me.
Thanks for all the help! I'm officially unstressed about this quiz.
Linking isn't a big deal.
The pickle was pdf = PDF = probability density function. Absolutely off but I kept thinking PDF was Portable Document Format.
Another day, another fact or factoid.
All righty.
The bottom line of this is that, as I can't solve the equation, don't need to program it, and my roots are technically in some other niche, I shouldn't be too fussed. Thank goodness.
Thanks, guys. I'll be sure to Wikipedia things (or as well) in the future.
— jean-baptiste alphonse karr, les guêpes (1849)
wiki subforum @ mtgs forums * mtgs wiki * site rules
I'm not certain what you mean by "solve the equation", but maximizing the log-likelihood gives you a closed form estimator, the GLS estimator. I'm not too familiar with incorporating Bayesian stats into that, but you should still be able to get an explicit result with a well-behaved prior.
How long oes it need to be? I mean, it can be done, it's just going to be way out of your comfort zone.
Done by Rivenor of Miraculous Recovery signatures!
It can be on anything you want? Then try and find a pretty general topic, so you can say vague things, and essentially whatever you want. Otherwise, you get stuck.
Done by Rivenor of Miraculous Recovery signatures!
Presumably meant to play off of this novel. The second section in that article (and possible more by following links) seems to have a couple of implicit pointers.