What would happen if you ran conductive nanowires all over the surface of the brain? For the sake of this argument we'll say that the wires are biocompatible. Would it be benificial or would it mess up the brain to have two different parts interconnected?
Programming languages
C++ is good for writing games
Objective C is good for IOS app
Java is good for Android app.
Any other examples of programming languages?
Objective C is good for IOS app
Java is good for Android app.
Any other examples of programming languages?
line integral, incorrect setup
1. The problem statement, all variables and given/known data
##\int_\mathscr{C} \vec{F}(\vec{r})\cdot d\vec{r}; \vec{F}(x,y,z) = <sin z, cos \sqrt{y}, x^3>## I am assuming ##\vec{r}## is the usual ##\vec{c}## used, so maybe this is where I am incorrect
3. The attempt at a solution
C goes from (1,0,0) to (0,0,3)
Parametrizing C
##\mathscr{C}: \vec{c}(t) = (1-t)<1,0,0> + t<0,0,3> = <1-t, 0 ,3t>; 0 \le t \le 1 ##
##\vec{c}\,\,'(t) = <-t, 0, 3>##
##\vec{F}(\vec{c}(t) = <\sin 3t, 1, (1-t)^3>##
##\displaystyle \int_{0}^{1} <\sin 3t, 1, (1-t)^3> \cdot <-t, 0, 3>dt##
##\displaystyle \int_{0}^{1} -t \sin 3t + 0 + 3(1-t)^3 dt##
I got this far and integrated it but got the wrong answer, I checked my integration already so I integrated this setup correctly but I screwed up on the setup somewhere.
##\int_\mathscr{C} \vec{F}(\vec{r})\cdot d\vec{r}; \vec{F}(x,y,z) = <sin z, cos \sqrt{y}, x^3>## I am assuming ##\vec{r}## is the usual ##\vec{c}## used, so maybe this is where I am incorrect
3. The attempt at a solution
C goes from (1,0,0) to (0,0,3)
Parametrizing C
##\mathscr{C}: \vec{c}(t) = (1-t)<1,0,0> + t<0,0,3> = <1-t, 0 ,3t>; 0 \le t \le 1 ##
##\vec{c}\,\,'(t) = <-t, 0, 3>##
##\vec{F}(\vec{c}(t) = <\sin 3t, 1, (1-t)^3>##
##\displaystyle \int_{0}^{1} <\sin 3t, 1, (1-t)^3> \cdot <-t, 0, 3>dt##
##\displaystyle \int_{0}^{1} -t \sin 3t + 0 + 3(1-t)^3 dt##
I got this far and integrated it but got the wrong answer, I checked my integration already so I integrated this setup correctly but I screwed up on the setup somewhere.
Chemistry Major Thinking (too much?) about Physics
I have been doing research in chemistry for quite a while now. I love chemistry! But for about a year now, all of the questions that I've had are of a more purely physical nature. My mentor has some good answers for me, but a lot of the time he doesn't seem to care or know about the answer. He has even explained before that a chemist: 1.) shouldn't concern himself with knowledge of the field I'm asking about, 2.) wouldn't find use for this information, and 3.) I wouldn't have time to learn that stuff in grad school for chemistry anyways.
I would love to take a degree in physics doing work in atomic, molecular and optical physics.
I don't know whether or not to continue with my pursuit of chemistry; I have a strong grad school application package and I should get into a top program. But should I go into physics to satisfy my curiosity? I would love if someone could help me by asking questions that might make my decision more clear.
Should I mention that I like math? I've looked at the physics GRE and I'd guess that I'd score pretty well on it. What's a competitive score on that thing anyways, 85th percentile? 90th? I'm sure that's subjective, but a random number guess or a ballpark will satisfy me.
Thanks.
I would love to take a degree in physics doing work in atomic, molecular and optical physics.
I don't know whether or not to continue with my pursuit of chemistry; I have a strong grad school application package and I should get into a top program. But should I go into physics to satisfy my curiosity? I would love if someone could help me by asking questions that might make my decision more clear.
Should I mention that I like math? I've looked at the physics GRE and I'd guess that I'd score pretty well on it. What's a competitive score on that thing anyways, 85th percentile? 90th? I'm sure that's subjective, but a random number guess or a ballpark will satisfy me.
Thanks.
Copper cathode experiment
Hi. I am a complete novice working on my first backyard experiment.
I have a 1part sulphuric acid 4parts tap water pregnant leach solution (from old copper mine tailings).
If I were to set up an electrolysis type experiment with a lead anode and a copper cathode should I expect all the metals (i.e. copper, iron, cobalt) in the solution to be deposited onto the cathode?
Thanks
I have a 1part sulphuric acid 4parts tap water pregnant leach solution (from old copper mine tailings).
If I were to set up an electrolysis type experiment with a lead anode and a copper cathode should I expect all the metals (i.e. copper, iron, cobalt) in the solution to be deposited onto the cathode?
Thanks
EV and Logic : My Brain Hurts
So, I'm having a pretty lazy day and decided to do some thinking. And, while this usually turns out to be a splendid idea, today it resulted in me hurting myself. Psychically.
So yeah. I've been through a lot of toy games trying to figure out a way to reconcile this all in my brain box, but here's the basic gist of it:
Part 1) I tell you to pull out a $100 bill from your pocket and put it on the table. I'm going to make you a proposition and you can either accept or decline. If you accept, I will flip a fair coin and you will call it in the air. If you win, you're forced to trade your $100 for $200 of mine that I will give to you in exchange. If you lose, you have to trade your $100 for $50 of mine. What is the value of accepting?
Part 2) I have two envelopes, one containing twice the amount of money as the other, and both containing some positive amount of money. I hand you one of them. You can switch anywhere from 0-100 times. If you ran it 101 times choosing a different number of switches each time, in which instance(s) would you do best?
Part 3) Same as Part 2, but this time you look inside before being given the option to switch. You find $10,000.
What difference, if any, is there between Parts 1 and 3?
So yeah. I've been through a lot of toy games trying to figure out a way to reconcile this all in my brain box, but here's the basic gist of it:
Part 1) I tell you to pull out a $100 bill from your pocket and put it on the table. I'm going to make you a proposition and you can either accept or decline. If you accept, I will flip a fair coin and you will call it in the air. If you win, you're forced to trade your $100 for $200 of mine that I will give to you in exchange. If you lose, you have to trade your $100 for $50 of mine. What is the value of accepting?
Part 2) I have two envelopes, one containing twice the amount of money as the other, and both containing some positive amount of money. I hand you one of them. You can switch anywhere from 0-100 times. If you ran it 101 times choosing a different number of switches each time, in which instance(s) would you do best?
Part 3) Same as Part 2, but this time you look inside before being given the option to switch. You find $10,000.
What difference, if any, is there between Parts 1 and 3?
Electrical distrabution Neutrals
Elecrical distrabution question if I may. I am not an EE and only an avid farmer with a nessesity for electrical knowlage. Here is my question. I am using two unlike transformers with the same values.( 5oKVA single phase 120/240-600V). Starting at the utility pole where I have 200amp 120/240V and a neutral of course. I am intending to abandone the neutral at this point and step up the two hots to 600V. On the other side I intent to step back down to 120/240 and use the centre tap of the transformer to re-establish the a neutral. Asuming that this makes sence here are my question.
Should I ground the centre tap of the transformer? Or should I only ground the nuetral at the ditribution panel?
OR... should I carry the neutral through the entire systeme from the Utility company?
I am concered that if I do this wrong I may create stress on the utity transformer or some sort of induction voltages in the system. Please some clearity on this would be a great help.
Should I ground the centre tap of the transformer? Or should I only ground the nuetral at the ditribution panel?
OR... should I carry the neutral through the entire systeme from the Utility company?
I am concered that if I do this wrong I may create stress on the utity transformer or some sort of induction voltages in the system. Please some clearity on this would be a great help.
Trapeze performer
1. The problem statement, all variables and given/known dataA trapeze performer swinging in a vertical circle can be modeled as a rotating bar pivoted at one end, as shown in figure 8.26. Let the mass of the bar be 70 kg with the center of mass located 1.2 m form the axis of rotation. If the angular velocity at the top of the swing is 3 rad/s, what is the value of w at the bottom of the swing? (hint use the principle of conservation of energy.)
2. Relevant equations
3. The attempt at a solution
I am not really sure where to begin with this problem. I was thinking that I could use kinetic and potential energy to solve this problem and basically convert the potential energy at the top to kinetic energy to find the velocity but it doesn't say how high the bar is.
2. Relevant equations
3. The attempt at a solution
I am not really sure where to begin with this problem. I was thinking that I could use kinetic and potential energy to solve this problem and basically convert the potential energy at the top to kinetic energy to find the velocity but it doesn't say how high the bar is.
Rotation motion problem
1. The problem statement, all variables and given/known data
A mass m1 is connected by a light cord to a mass m2, which slides on a smooth surface. The pulley rotates about a friction less axle and has a moment of inertia I and radius R. Assuming the cord does not slip on the pulley, find (a) the acceleration of the two masses, (b) the tensions T1 and T2, and (c) numerical values for a, T1 and T2 if I = 0.5 kg * m^2, R = 0.3 m, m1 = 4 kg, and m2 = 3 kg. (d) What would your answers be if the inertia of the pulley was neglected?
2. Relevant equations
3. The attempt at a solution
I drew a free body diagram and tried to find the acceleration of the first block. So I did
-9.6m1 + T = m1a1
-9.8 + T/m = a1
unfortunately this is not even close to being the right answer. How should I approach this problem?
A mass m1 is connected by a light cord to a mass m2, which slides on a smooth surface. The pulley rotates about a friction less axle and has a moment of inertia I and radius R. Assuming the cord does not slip on the pulley, find (a) the acceleration of the two masses, (b) the tensions T1 and T2, and (c) numerical values for a, T1 and T2 if I = 0.5 kg * m^2, R = 0.3 m, m1 = 4 kg, and m2 = 3 kg. (d) What would your answers be if the inertia of the pulley was neglected?
2. Relevant equations
3. The attempt at a solution
I drew a free body diagram and tried to find the acceleration of the first block. So I did
-9.6m1 + T = m1a1
-9.8 + T/m = a1
unfortunately this is not even close to being the right answer. How should I approach this problem?
Search engine broken
I've searched the forum for "Quantum Cheshire Cat" both internally, and via google. Although it appears that the key words are/were there:
Via google:
The third match gives me a 404 error.
Was the thread deleted, or have I forgotten how to search the forum?
Via google:
#1Direct product of space and spin in hadrons
... inertial self-propulsion design for snowman-like nanorobot • The Quantum Cheshire Cat: Can neutrons be located at a different place than their own spin?
http://ift.tt/1lhAM8D
#2Confused about wavefunctions and kets
... inertial self-propulsion design for snowman-like nanorobot • The Quantum Cheshire Cat: Can neutrons be located at a different place than their own spin?
http://ift.tt/1uN0xHA...
#3Physics, math and God
... inertial self-propulsion design for snowman-like nanorobot • The Quantum Cheshire Cat: Can neutrons be located at a different place than their own spin?
http://ift.tt/1lhAKO0...
#4Quantum tunneling in the Sun
The Quantum Cheshire Cat: Can neutrons be located at a different place than their own spin? • A transistor-like amplifier for single photons ...
http://ift.tt/1uN0z28
The third match gives me a 404 error.
Was the thread deleted, or have I forgotten how to search the forum?
Why is there so much emphasis on whether osomething is a function
I was tutoring someone for an intro mathematical logic class and there were a few problems about proving something is a function or not. I remember in high school algebra, there were a pretty large emphasis on the vertical line test. In precalculus I saw it again. In calculus I saw it again. In this intro to logic course there was proving that something was a function.
Why does it even matter? After intro to logic I have never really seen a reason why we even care. The only place where it even matters is in complex analysis when you have to define branch cuts for multivalued functions. But it really wasn't that big of a deal, and most people who take high school algebra won't see complex analysis. I could kind of see in a logic class, as an example of proof. But it seems strange that after that class, I have never seen it come up again really. In math or physics or science or anything really.
Why does it even matter? After intro to logic I have never really seen a reason why we even care. The only place where it even matters is in complex analysis when you have to define branch cuts for multivalued functions. But it really wasn't that big of a deal, and most people who take high school algebra won't see complex analysis. I could kind of see in a logic class, as an example of proof. But it seems strange that after that class, I have never seen it come up again really. In math or physics or science or anything really.
Electrical distrabution question
Elecrical distrabution question if I may. I am not an EE and only an avid farmer with a nessesity for electrical knowlage. Here is my question. I am using two unlike transformers with the same values.( 5oKVA single phase 120/240-600V). Starting at the utility pole where I have 200amp 120/240V and a neutral of course. I am intending to abandone the neutral at this point and step up the two hots to 600V. On the other side I intent to step back down to 120/240 and use the centre tap of the transformer to re-establish the a neutral. Asuming that this makes sence here are my question.
Should I ground the centre tap of the transformer? Or should I only ground the nuetral at the ditribution panel?
OR... should I carry the neutral through the entire systeme from the Utility company?
I am concered that if I do this wrong I may create stress on the utity transformer or some sort of induction voltages in the system. Please some clearity on this would be a great help.
Should I ground the centre tap of the transformer? Or should I only ground the nuetral at the ditribution panel?
OR... should I carry the neutral through the entire systeme from the Utility company?
I am concered that if I do this wrong I may create stress on the utity transformer or some sort of induction voltages in the system. Please some clearity on this would be a great help.
Rotations Per Minute Needed to Balance a Top
I have little to no experience with this area of physics, so don't assume I know certain things. A cone is spun (with the tip down) at a constant, not decreasing, RPM (Rotations per Minute). What is the minimum RPM for it to stay there without falling, and (if possible) the minimum RPM necessary to make it seem as thought it might be stationary? If dimensions are needed, I would not be able to give them, but I can give ratios, or I can put it in units that have no real world value.
Vector Potential
Does the vector potential have physical significance or is it just a mathematical tool? What is your interpretation of Aharanov-Bohm effect? Are "gauge choices" really a choice or a restriction? It seems like gauge choices are really gauge conditions, and in some sense, a restriction. Thoughts? Thanks.
Impedance defined?
Hi,
I was reading Charles Steinmetz "Theory and Calculation of Alternating Current Phenomenon" and on page 89 (can be found online easily) Steinmetz defines impedance as: Z = R - jX, but see it commonly defined as R + jX. I read on wikipedia there are two impedance equations for capacitive impedance and inductive (R - jX, R + jX), but Steinmetz doesn't mention either or suggest this is a special case of impedance, just that it applies for alternating waves.
So, did Steinmetz make a mistake in his definition? How do we know which impedance he is talking about?
I am confused because I doubt Steinmetz defined it incorrectly, yet don't know where the sign difference comes from? I get the wikipedia explaination of phase difference, but Steinmetz says its the impedance, I don't think he meant just capacitive or inductive.
EDIT: Looking further into the book, he only uses Z = R - jX throughout the whole book, seems to be the general definition, regardless of inductive or capacitive
Thoughts? Thanks.
I was reading Charles Steinmetz "Theory and Calculation of Alternating Current Phenomenon" and on page 89 (can be found online easily) Steinmetz defines impedance as: Z = R - jX, but see it commonly defined as R + jX. I read on wikipedia there are two impedance equations for capacitive impedance and inductive (R - jX, R + jX), but Steinmetz doesn't mention either or suggest this is a special case of impedance, just that it applies for alternating waves.
So, did Steinmetz make a mistake in his definition? How do we know which impedance he is talking about?
I am confused because I doubt Steinmetz defined it incorrectly, yet don't know where the sign difference comes from? I get the wikipedia explaination of phase difference, but Steinmetz says its the impedance, I don't think he meant just capacitive or inductive.
EDIT: Looking further into the book, he only uses Z = R - jX throughout the whole book, seems to be the general definition, regardless of inductive or capacitive
Thoughts? Thanks.
Question regarding the universes origin
According to the Poincare recurrence theorem - certain systems will, after a sufficiently long but finite time, return to a state very close to the initial state.
and according to wikipedia - a quantum fluctuation or vacuum fluctuation is the temporary change in the amount of energy in a point in space,as explained in Werner Heisenberg's uncertainty principle.
and according to wikipedia again - a bubble of lower-energy vacuum could come to exist by chance or otherwise in our universe, and catalyze the conversion of our universe to a lower energy state in a volume expanding at nearly the speed of light, destroying all that we know without forewarning. Chaotic Inflation theory suggests that the universe may be in either a false vacuum or a true vacuum state.
Is it possible that in a universe such as ours that expands forever and reaches heat death will have regions where all these occurrences happen at the same time; thereby birthing a new stable universe that is part of, yet separate from our own.
and according to wikipedia - a quantum fluctuation or vacuum fluctuation is the temporary change in the amount of energy in a point in space,as explained in Werner Heisenberg's uncertainty principle.
and according to wikipedia again - a bubble of lower-energy vacuum could come to exist by chance or otherwise in our universe, and catalyze the conversion of our universe to a lower energy state in a volume expanding at nearly the speed of light, destroying all that we know without forewarning. Chaotic Inflation theory suggests that the universe may be in either a false vacuum or a true vacuum state.
Is it possible that in a universe such as ours that expands forever and reaches heat death will have regions where all these occurrences happen at the same time; thereby birthing a new stable universe that is part of, yet separate from our own.
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