Magnets Definition and 562 Threads

Homework Statement Bringing a strong magnet close to an operating incandescent light bulb has the effect of breaking the filament. Breakage might be expected when the extra force on the filament becomes comparable with gravity. Estimate the field strength likely to cause problems with a...

1. Determining the relationship between initial speed of a cart (with magnets, aligned with and moving towards magnets on a wall) and the stopping distance from the wall) 2. Kinetic energy(Ke)=Magnetic potential energy(Mpe) Ke=mv^2/2 Mpe=km1m2/r mv^2/2=km1m2/r...

Greetings I've been reading about these magnets such as these: http://www.lanl.gov/orgs/mpa/nhmfl/magnets.shtml Take a look at the pulse durations (it says in notes at the bottom "Total pulse length including decay" It's all nice but I don't understand one thing. How can they make...

Hi everyone, I've been trying to find info about getting an object to levitate and how strong the magnets need to be but haven't had much luck. I'm trying to build a levitating picure frame using permanent magnets rather electromagnets. The plan was to take apart a lamp and put in two ring...

Homework Statement Part A- Charges and Fields 1. Click on the category named Electricity, Magnets, & Circuits, then find Charges and Fields, click on it, then select Run Now!. (You may need to install Java onto your computer) 2. Select Grid and Show Numbers in the green menu box. Place equal...

It is my understanding that the force between magnets relates directly to the shape of each magnet. To annul the shape of the magnet, I am seeking a formula that describes the force between two magnets in terms of magnetic flux density. My Question. If two permanent magnets faced each...

Since everything has to obey the law of conservation of energy, where do magnets get their energy from? They can lift something up through a gravitational field which requires energy. If the energy for a solid state magnet comes when you magnetize it (e.g. moving it with your hands with another...

I figured with how big the internet is, there would be an entire forum on magnets somewhere out there for me to ask my question but it turns out, if it does exist, I couldn't find it. So I figured you guys would be just as good, if not better :smile: I'm building an object that has 2 halves...

I know this is probably wrong and that my understanding of physics is basic. But figured id just share a quirky idea I had and see if anyone can explain to me why it wouldn't work. O.k. Imagine two huge magnets in a chamber. One is positively charged and one is negatively charged. And they are...

Homework Statement The figures below show two different situations where a current may be induced in a loop according to Faraday's Law, with the direction given by Lenz' Law. The magnetic field is shown by the x's in Fig. 2. Select ALL correct answers (i.e. B, AC, BCD) for the current in the...

I want know that can we build a long Permanent magnet for a Maglev way ? Please say that its possible ? (i attached one picture , with that you can understand that what is my question and what is a long Maglev way by a Permanent magnet)

Magnetic Materials - http://www.aacg.bham.ac.uk/magnetic_materials/ Table of Contents History of Magnetic Materials Origin of Magnetism Magnetic Units & Terminology Classification of Magnetic Materials Intrinsic Properties of Magnetic Materials Magnetic Domains Magnetic Hysteresis...

I have read in quite a few places that you can pass a wire through a magnetic field and this will produce electricity. Does the polarity of the magnet have any effect on this or is it just the fact that it is a magnetic field? To be a little more specific, if you had a wire setup next to an...

How are magnets made? I mean how are they made to produce a magnetic field? How are some magnets made to attract and some to repel? And just to know:- Does magnetism got some connection with gravity? Because practically we can notice some similarities.I think I am asking an answer to silly...

Hi there. I got two questions for you: 1- How can I calculate the force of attraction in Newton of two bar magnets of about 5 cm long and 2 cm wide separated by a few centimentres? 2- If I want to reduce near to nothing the attraction of these two magnet (whil still kept at the same...

So i have decided for my physics project to build a magnetic linear accelerator made with half inch ball bearings on a plastic track. The first bearing is rolled and accelerated by the magnet which when struck, launches the ball on the other side due to the momentum of the accelerated bearing...

Hello, I was doing some questions and I thought I was understanding solenoids and magnets in incorrect way.. The question was, what would you feel if you bring a magnet close to a solenoid. I've wrote 2 possibilities, first is that they will repel and the second is that the solenoid would...

Homework Statement A strong magnet is placed on the screen of a television set (permanently damaging the tube). Explain the following observations. a) the picture becomes distorted b) the screen is completely dark where the field is strongest Homework Equations none. The Attempt...

Is it possible to extend the range of an electromagnet? How would one do this?

I know this doesn't pertain so much to engineering but I figured you guys would know best. If you set the magnet next to a cell phone or TV, what kind of damage would be expected?

Hello, I am new to the forum, thus please be patient with me. I have a little bit of a problem... Currently working with magnets. Basically, I need to derive an equation for the attractive/repulsive force between two magnets given a distance between them. The most important thing is that...

1) An electromagnet with north up 2) A paddle 3) A permanent magnet (magnet A) positioned north down on top of the left side of the paddle 4) A permanent magnet (magnet B) positioned south down on underneath of the right side of the paddle Reasoning) If the electromagnet is turned on from...

They pull a lot of pounds in ratio to their size, I was wondering if it would make any difference in the energy output if you replaced the normal magnet with a neodyniam.

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...

hello guys, I finally decided to join a forum online and starting asking my " brilliant" :-0 questions..hehehe..oh man i have plenty of those.. OK, am reading the book: understanding physics, by isac asimov. And i am reading about magnetisim now, and its stated two things that bugged my...

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...

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 properties, such as residual...

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...