I am, along with two of my classmates, are planning to make a prototype of a scooter (as in slower, smaller version of a motorcycle) that is propelled by an infinitely turning magnet wheel. Not as a motor or something that converts the motion to electricity, but as an independently perpetual motion-machine that may lead to the movement of the wheels of the scooter. But we have no blueprint or any plan on how to make that happen. Other than this, we are completely clueless on how to make brakes for this type of thing, how to control the speed, and how will generally work as a whole. We're eighth grade students and are probably going to never have a proper research if this doesn't work.
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There are many videos on youtube in which people arranged magnets in circle and rotated one placing in middle of that circle on a shaft, and the magnet (magnet motor) starts madly and continues its movement. Do they really rotate infinitely? If so, do they from where they get that extra energy to move so fast and infinitely?    EDIT: This question is about real world scenario  UPDATE: I am unable to find that particular video about which i talked about -- I added them to my favourites, but they are all now deleted :( -- there are hundreds of that that kind of videos. Some example videos links
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In , a dry cell battery, a wound copper wire and a few magnets (see image below) are being used to create what can be described as "train". It looks fascinating but how does this experiment work?  Update 8th August 2016: This problem has been completely worked out in a paper that was published in the January 2016 issue of American Journal of Physics.     Link: Am. J. Phys. 84, 21 (2016);
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I was just watching a mega factory video and wondered why they use an AC motor which requires a power inverter instead of DC which may be powered directly from their DC battery? Introducing an inverter means more cost (weight, controller, etc).  Are there any reasons for that? What are the differences between an AC and DC motor that may have lead to this decision? Also does anyone know what kind of motor is used in other electric cars?
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I understand the field magnets attracting/repelling the armature/coil so that it turns one half-turn and then, because the commutator is turned, its contact with the brushes has switched sides, and the current goes in the opposite direction, reversing the electromagnetic polarity. Then, because the polarity is swapped, it attracts/repels to complete the second half-turn. The thing is, isn't it a bit of a gamble that it will turn in the same direction? Couldn't the it just be pulled/pushed back, more or less undoing the half-turn?  I'm also a bit confused how the rotation doesn't just stop once the commutator is oriented so that the brushes are contacting both sides of the commutator. In other words, there's a brief period just as the commutator switches the current directions where each both the brushes are in contact with both sides of the commutator where the current is neutralized. Shouldn't this stop the motor?    For reference, I'm just talking about a simple DC motor.
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So I have these two wheels parented to the leg of a robot. I wanna make them spin a few times but they're spinning around the wrong axis. With other objects I could just press R, Y, Y to make them spin right when they're already at an angle, but for some reason it doesn't work with these. Would be amazing if someone helped me fixing this!
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I was going to add a bit of information to my post on a previous day using schematics and some instructions. What programs are being employed for this purpose?  I mostly want to see what others are using and that I can easily use to give descriptive schematics.  In a perfect world, and I know this is a case of me wishing, it would be:   Free. Extremely easy to draw schematics in. Allows simple production of waveforms for the inputs/outputs.
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Recently a  set a record for sailing a wind-powered land vehicle directly down wind, and a speed faster than wind speed. Wikipedia has a  talking about it, but it doesn't explain exactly how it works.  I can imagine some configurations, but I don't get how a system could be set up to push forward with a tailwind (when the cart is moving slower than the wind) and push forward with a head wind (when the cart is moving faster than the wind).  Could someone help explain how this is possible?
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I don't know how this "paradox" can be solved. I'm given the following system: A permanent magnet with a magnetic field given by ($\hat{a}$ are unit vectors in the x and y directions)  $$\vec{H}=H_0\hat{a}_y$$  and a parallel plane capacitor with an electric field  $$\vec{E}=E_0\hat{a}_x$$  Poynting's vector is given by:  $$\vec{S}=\vec{E}\times\vec{H}=H_0E_0\hat{a}_z \neq 0$$  The funny part comes when the professor told that in a system like that "clearly" there is not propagation (wich I know will imply some short of energy flux) in the $z$ direction, hence the "paradox". Is there or is there not propagation of energy?  Any hint will be appreciated, thank you for your time.
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On a Physics specification, it says:     6.7 Know how to use two permanent magnets to produce a uniform magnetic field pattern.   Isn't it "produce an uniform magnetic field", or is the existing "produce a uniform magnetic field pattern" correct?
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I want to design a standalone dynamic braking circuit for AC motor driver , because to deal with regenerative energy that the AC source cannot handle causing a DC bus voltage Rise . The concept is well established in many resources online that senses the DC bus voltage and dissipates the access energy in a " Brake Resistor ".    I want to know what is usually used circuit that is called in the diagram as "chopper module" and design it without micro controller if possible.  I donot know of an IC that is designed for this purpose solely , so what comes to mind is comparator with hysteresis with a low side gate driver to open/close Braking mosfet. but no so sure if this is a decent choice until i test in reality and see how well it will work.  My concept test circuit :      So I would like to know your comments on the subject, and corrections if i am missing something here .
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I'm interested in learning physics. I do realize that the subject is large and that it would be easier if I had a specific area of interest. However, I do not. I suppose I want to learn about the fundamentals of it all; the axioms that combine all physics fields. Or, in other words, a high school physics class.   Specifically, a book or series of videos would be helpful. I looked over MIT and unfortunately the material wasn't for me. I don't mean to be "picky" so I am not completely ruling out any resource just yet.   Thanks in advance.
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[ (the file model working ^^^^^)this is my model bellow (1)    (my attempt at translating your work ^^^^)I want it too spin like in this Youtube video tutorial(2)
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Problem #25 from the 2009 $F=ma$ contest:     Two discs are mounted on thin, lightweight rods oriented through their centers and normal to the discs. These axles are constrained to be vertical at all times, and the discs can pivot frictionlessly on the rods. The discs have identical thickness and are made of the same material, but have differing radii $r_1$ and $r_2$. The discs are given angular velocities of magnitudes $\omega_1$ and $\omega_2$, respectively, and brought into contact at their edges. After the discs interact via friction it is found that both discs come exactly to a halt. Which of the following must hold? [...] Ignore effects associated with the vertical rods.   Diagram here:     Probably conservation of angular momentum is useful here, but I am not clear how it can be applied. There are two distinct axes of rotation, one for each disc, so we cannot talk about conservation of angular momentum about one axis. If the two disks rotated about the same axes then the solution is straightforward, but this is not the case.
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I want to build a small , but how is the power (and if possible a communication line) transmitted to the spinning part?  I've looked at some POV project, but they usually don't explain that part much...
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I am planning to build an electronically controlled automatic bike transmission for my senior design project. I'm personally more of an electrical guy, so dealing with the mechanics is somewhat new to me. I would have loved to use an off-the-shelf electronic derailleur, but alas, they are too cost prohibitive (the school has allotted a budget of $115 per student and we're a group of two, so we have $230 to spend). So I'm going to need to make my own like several other people have done.  I am planning on using the bike's current derailleurs and replacing the hand shifters with motors of some sort to pull on the cables. Of course, we're going to need a certain amount of torque to shift up (and much less for shifting down) and a holding torque to ensure that we don't accidentally slip down a gear.   I have not bought a bike yet, I'm looking at a Diamondback bike that I found on Craigslist (it looks like a hybrid bike). So I'm wondering if there are any average measurements for the required torque.  And of course, I'm sure there are many people more experienced in bicycling than I am. So if you have a better solution, please feel free to shout it out. I'm all ears.
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As an electric motor spins, the energy from the electricity is 'conducted' to the rotor by the magnetic fields.  However, when the motor is stopped, the energy becomes heat and burns up to motor.  What causes this heat to be formed?  Is it purely generated by the current flowing through the wire or is the magnetic field form the permanent magnets involved somehow?  Conversely, why is there less heat when the motor is spinning?  I'm hoping this is not just because the motor contains a fan.
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"Now we turn our attention to what happens in $S'$, in which the particle is at rest and the wire is running past (toward the left in the figure) with the speed $v$. The positive charges moving with the wire will make some magnetic field $\ B'$ at the particle. But the particle is now at $rest$, so there is no magnetic force on it! If there is no magnetic force on the particle, it must come from an electric field. It must be that the moving wire has produced an electric field. But it can do that only if it appears $charged$-it must be that a neutral wire with a current appears to be charged when set in motion."  So i got this from Feynman's lectures in physics volume 2 pg 13-7 and 13-8. I find it hard to believe that the particle experiences no magnetic force due to the moving wire although it's stationary. Since this is classical and not quantum electrodynamics if we assume the charged particle to have inertia, then by Newton's second law, the particle will remain at rest until acted upon by an external force, which i assume is the $magnetic$ $wind$ created by the moving wire past the stationary charged particle. Could someone please clarify??