Magnets Definition and 538 Threads

Homework Statement Two blocks are free to slide along a frictionless wooden track ABC as shown in Figure P9.20. The block of mass m1 = 5.02 kg is released from A. Protruding from its front end is the north pole of a strong magnet, repelling the north pole of an identical magnet embedded in the...

In school yesterday I was doing a practical and when I moved a small 1.5T block magnet near a rheostat the magnet started vibrating, why does it do this?

If you combine many small magnets together in a cube or spherical shape (say those 1.5 tesla rare Earth magnets), is the resulting magnetic field able to affect even heavier objects, or is there no difference in the range/energy of the field?

Just a few simple questions about magnets: 1) If 2 permanent magnets are placed one on top of the other such that one magnet repels the other and therefore the second magnet levitates and assuming that this is a ideal situation and the magnet is not knocked off its vertical levitating...

Hi everyone Im an engineering student currently working on a group project. Part of the project is to use a electric magnet and a permanent magnet to balance a weight on the end of a cantilever (digital scale effectively). We would then measure the current through the electromagnet to...

Hi everyone! As I understand it, magnetism can be explained by special relativity when charges are moving - length contraction in different frames of reference leads to coulomb forces between the charges in these frames. But how does magnetism in a permanent magnet arise? Are there...

The magnetic field inm the gap of the toroidal permanent magnet is 0.50 T. The length of the magnetic circuit is 20 cm and that of the gap is 1.0 cm. what are the magnitudes of i) B in the material ii) H in the gap iii) H in the material iv) M in the material The Attempt at a Solution...

Hi, I got hold of a set of kitchen weighing scales which are made of some ferromagnetic plate and my neodymium magnets. So the reading on the weighing scales increases as you bring the magnet near the weighing plate, as expected... they then reach a maximum just before you touch the magnets...

Magnets at the speed of light. I guess that if you propel a (natural) magnet close to the speed of light then nothing unusual happens to the magnetic field because it already exists and is accelerated along with the magnet, but what happens to an electro magnet? If an electro magnet is...

Hi All, Do equations (or branch of study) exist for the following problem: I have two (or more sphere magnets); can it be determined mathematically/classical-physics-equations what positions these two magnets will attract each other in and lock ? In other words - these two sphere...

I know that electricity running through a circuit produces a magnetic field...does this work the other way around? Does a permanent magnet in a circuit produce electricity? A colleague of mine is trying to convince me that moving a magnet back and forth in the presence of a circuit can produce...

How do you calculate the attraction and repulsion forces between two magnets? I know it depends on many factors, so for example: two 0.5"x0.5"x0.25" Neodynium magnets with a grade of 42 (Br = 13200 Gauss) that are 0.25" apart from each other (only air is separating them). Thanks for any help...

What's the theoretical maximum force? At a certain distance & per kg, i guess. How would you go about calculating this?

I am interested in the effects of temperature on Permanent Magnets. I understand that Neodymium magnets lose -0.09 ~ -0.13% of Br/°C and can work stably under 80°C for low Hci Neodymium magnets. However, what happens to them just over this 80°C limit? Do they still have some magnetic strength...

Hi, Would an electromagnts or solenoid behave any different if a permenant magnet was attached to it when it is powered up? For example, if I had a opposing pole type electromagnet and I attached the north pole end of a permenant magnet to the north pole end of the unpowered electromagnet. Now...

So we can think permanent magnets to be composed of large number of tiny magnetic dipoles? You can hear this in very elementary introductions. I would guess this is some kind of approximation to the spins of the atoms, or something... There is energy stored in the magnetic field, so if these...

hey ; with magnets we use North and South but for example : what does north stands for ; indicate ? i mean, if u have for example a magnetised material lets say u got it magnetised by rubbing it with an other if the material has more positive charges than negative : do we say its a Norh...

Our teacher wants us to construct a speaker that can provide sound (that can be heard from anywhere within the classroom) when connected to wires that are hooked up to some sort of device. I'm unsure of where to start and where to get the supplies. Since we are on the magnetism course, I know...

source:British physics olymp. 1995:cool: a small slab of material is placed on a dish containing liquid nitrogen.The material is a superconductor at the temperature of liquid nitrogen.A small but strong magnet is moved near and placed over the slab.The magnet is seen to wobble but remains...

Magnets and electromagnet power? It’s said in the <crackpot link removed - Zz> e-books that high voltage 5000v DC electromagnets are more powerful that low voltage 12V DC electromagnets. And in the permanent magnet motor it’s said that “The Attraction of a magnet ( North ) is always stronger...

Homework Statement Why should bar magnets be stored in pairs with soft iron keepers across their ends? Homework Equations none The Attempt at a Solution Is it to prevent damage?

I am wondering if there is a way to put shielding on a simple magnetic bar mad out of neodymium so that the magnetic field is not emanating from all over but just at the ends. I/E a magnet shaped like a can of soda. Putting some type of Shielding on what would be the label section so that the...

Does a permanent magnet ever loose it's energy or decrease over time? I read somewhere that a "fixed" magnet's energy will dissipate in time as it does work. I don't know what they mean by fixed. Also, will a permanent magnet work without the Earth's energy (eg. in space).

There are lots of patents on Neo magnets and they are difficult to sort out. Some of the patents restrict the use of the magnets that contain cobalt and/or have a tetragonal crystalline structure. Does someone know: What types of magnets contain cobalt? What types of magnets have a...

[FONT="Tahoma"] Hello! I have a deeply magnetizing question. I have an attractive magnetic assembly and I am interested in finding some forces, acting on its parts. Set-up details ( if to be specific ): I have two cylinder-shaped neo magnets with identical dimensions and...

Hi all, i saw many times while browsing that persons like howard johnson, tom beardson, paul monus, etc., are informing themselves that they have invented motors that run only based on the stored energy of the permanent magnets... are they really having that machines..? if yes, i...

Hi, I hope this is the correct place to ask this. Does anyone know of a formula to calculate the force of attraction or repulsion between two magnets of diffirent sizes and strengths? Also the magnets are not parallel to each other. Any help highly appreciated.

Hey all, New poster here that will be back to ask and answer seeing as how well versed you all are. My current dilemma deals with a moving charge and the magnetic field it produces. (sorry if this is in the wrong area of the site) Basically it's this: Consider a charged particle moving...

I understand that in the bell theorem photonic spin is in a superpoistion state until one observes it. Is that also the case with electrons? If so then how come magnets are magnets? Surely the electrons already made up their minds which way their north and south magnetic poles are pointing...

Hi all ! I've looked at a strange video on the net of an obscure compagnie that pretend to create electricity (5 times more energy than it consume). This video was very entertaining, I laughed a lot. But, there was something special that intrigate me... The pseudo-scientist take a permanent...

I was surprise to find that even HowStuffWorks.com didn't have an article for 'permanaent magnets'. I was wondering, do permanent magnets always have magnetic fields aroung them? What makes them permanent?

Hi all, In one of the books I'm reading, it says that shields are only used in the presence of alternating fields. However, in some websites, I see people using magnetic shields for permanent magnets which has a magnetostatic field. I ran some simulations, and the filed of a permanent magnet...

Hi all, I have this simple question that I never really understood. A permanent magnet generates a magnetic field around itself. Is there an electromagnetic wave propagation associated with this permanent magnet? If so, what is the frequency of the wave? Thanks, Mike

Is it possible to produce electricity by using permanent magnets with no moving parts? I believe that is possible. Because AC current produced by moving armature or copper wire or some other metal in magnetic field. Then without moving wire it should produce DC or some kind of electron flow...

I have a few questions about permanent magnets: What are the most powerful permanent magnets made of? How strong do they get? What are the ways to make an already powerful magnet even stronger? I understand that placing iron behind it will amplify it. Why? I also read somewhere...

Electro magnets / DC / metal wire / vibrating? Hi, just a very basic question: I just tried making my own electro magnet (copper coil, steel core, connected to a 12V 2A DC power source) and i noticed that when i hold a metal wire (or just anything that's normally attracted by magnets) in...

hi all, Please can you help list materials that can be used to Block, Reduce, Stabilize, Increase or react with the fields from perminant magnets il start with Graphite: A Magnetic Stabilizer Coper: A Magnetic Inductor

I'm stucked on a practical in which I was supposed to find out how the magnetic force on a current carrying conductor depends on its length, current through it and the magentic field strength. After this I was supposed to plot 3 graphs. Well, I carried out the expt. using a current balance...

If the size of a magnet does not determin its strength, then what physical property does? THANX:smile:

The magnetic field around a magnet very much looks like the solution of a differential equation (which I guess it is, at least apprx). Now, can anyone give my a few simple exaples of such differential equations describing a magnetic field around a magnet?

Hi all, I need to create a very large magnetic field say 1Tesla (10000 Gauss). But I can not afford to build large electromagnets like the MRI machine. However, I have two permanent magnets that will create a static field of 5000 Gauss. My question is: can I superimpose magnetic fields...

Magnet A has twice the magnetic field strength of magnet B (at equal distance) at a certain distance and pulls on the magnet B with a force of 30N. Determine the force with which magnet B pulls magnet A. Could someone help me. I'm just starting physics in hs.

I have a formula, taken from Wikipedia: http://en.wikipedia.org/wiki/Magnet#Calculating_the_Magnetic_Force" But I didnt get the meaning of "mu" in this formula.. can anyone explain?

I was thinking of building something but I first must know a little bit more about magnets. First of all where could I buy good magnets of all sorts, with different strengths. Are there any stores like home hardware or renodepot that are known for selling magnets? Would they sell very...

is it posible to make a magnet rotate around a center point, with the use of other magnets?

I know that if you put a magnet in a coil of wire and turn it you can generate electricity, but a friend told me the more coil you use to take more electric you try to make the harder the magnet is to run, the same if you reverse it, even if you turn the coil. Why?

Ive been wondering if an electromagnet of great power has an effect on the human body, say the blood(containing iron). That is why I've been trying to bild one but all of my attempts have come out unsucesful.

Is there a substance that can be placed between two magnets that will stop one from affecting the other? If a sheet of paper is placed between the magnets it has no affect. This is obvious but what i want is a substance that can be placed between two magnets that are placed very close together...

Hi gang, Here is an easy one but nevertheless requires formula to express your postion. in terms of magnetic propulsion; I am building a tunnel with r=5cm and a sphere inserted will be approx 8cm diameter which will be propelled via electro magnetic propulsion. I'm now about to evaluate...

If I used two magnet, each being able to lift a load of 100 lb, to repel each other, what will be the total repulsive force ?