What advantage has a horseshoe magnet over a bar magnet?
110263
The poles in the horshoe are close to each other , so , more magnetism
146783
regular magnet is a permanent one and electromagnet is an artificially created magnet which behaves as a magnet when current is passed through a wire around a iron bar\nelectromagnets are widely used
76483
cobalt can be used just about anywhere iron could. the primary place would probably use in magnets
118123
There is a force applied to the permanent magnets equal to the force applied by the armature, but since the permanent magnets are usually attached to something huge they don't move much.  So there is little work done on them and so they don't eat up power.\n\nIt's just like asking "if I stand facing a wall and use my arms to push away from it, where did the power go in the wall".  It barely moves, so it absorbs very little power.\n\nSome power does go into the permanent magnet, due to the effects mentioned in the answer above, but it is generally small.
131979
a soft iron core increases the strength of an electromagnet, because iron a good conductor of electricity, and unlike steel it can be turned on and off, whereas steel is a permanant electromagnet.
88029
Advantages:\n\n1) Our stereo speakers use them.\n2) They are very useful for displaying things on the refridgerator.\n3) They are very useful in finding small metal objects we've lost.\n4) They can be used for mass transportation, like a monorail.\n5) They can be used to make a compass.\n\nDisadvantages:\n\n1) Other people's car stereo speakers use them even when you don't want to hear it!\n2) They can erase magnetic media.\n3) They can destroy a television set.\n4) They are only effective with certain metals.\n5) Devices that depend on them can get messed up in an electrical storm.
856860
You would need to have the magnet moving, and the power it would take to make it move would be more than any advantage you get out of it. Laws of Thermodynamics.
52641
A material which is predominantly diamagnetic will be repelled by a magnet, although typical objects only feel a very small force. This can be used to levitate light pieces of pyrolytic graphite or bismuth above a moderately strong permanent magnet. As water is predominantly diamagnetic, this property has been used to levitate water droplets and even live animals, such as a grasshopper and a frog.
1161474
You can't. The polarity of a magnet is set. If you screw it up, sorry!
1092759
I had the same problem when I learned about both of them. \nBut now think of it in a different way. You are assuming that the magnetic FORCE that magnets have on certain metals. But if you think about it carefully they don't create or destroy energy. \nIf you don't beleive me consider a piece of iron with only gravity working on. But its height is 0 so it has no Potential or Kinetic energy. But now let's say you bring in a magnet. Now naturally that will make the iron bar rise and stick to the magnet. Now a natural assumption would be that you just created potential energy because the height of the iron bar just increased. But now you have to consider the fact that magnet is still putting some force on the Iron bar. So no change in potential energy occured. No change in Kinetic energy occured once the bar stuck to it. and the Energy needed to bring the bar up could be accounted by the energy needed to bring iron bar in. This shows that there was no energy created.  \nI think that you are trying to overthink the problem. I think this should help good luck.
154800
From what I know about permanent magnets, the heat is the killer when you get near the transistion temperature of the material.  When you do this, the magnetic domains become randomly aligned again and the pole force gets reduced.  If you keep heating it, you can totally demagnatize the material.  In fact, during the manufacturing process, the material is heated very hot under a very strong magnetic field and cooled, allowing the aligned domains to be "frozen" making a high force pole.  \n\nSo in motor design, the aerodynamics of the rotor, the eddy currents generated while running, and the torque loads, will all contribute to heating the magnets.  If you can master the thermal design, you can make very powerful motors.
454527
wrap the bar in insulated copper wire, preferably solid core, keeping the wraps smooth and close together, and wrap three layers deep- when you reach the end of the first layer just wrap back towards the end you started at, same thing on third layer- them hook a DC power supply to the ends of the wire wrap, and let the thing run for 3-4 days (make sure when you hook it up that it doesn't heat much if any) pretty soon you've got a magnet.
35844
Log on to http://en.wikipedia.org/wiki/Magnet\n\nand check out Characteristics of magnetic materials
206699
Depends on what you mean by block the effects. Stainless is transparent to magnetism much like glass to a flashlight, ferrous (normal) steels will "pipe" the magnetism to a new direction, and Aluminum will scramble the magnetism.\n\nThis scrambling of the magnetism by aluminum is used by modern roller coasters as a braking device. Powerful magnets are on the vehicle and the aluminum is attached to the guideway. When the two get close toghether the scrambled lines of magnetism have the effect of removing energy from the moving vehicle (slowing it down) and heating up the aluminum.\n\nTry this: while not in the presence of steel, hold a powerful magnet in your hand. Swing your arm back and forth, note how freely your hand moves. Now swing your arm close to, but not touching a plate of aluminum. When you get near the aluminum your arm will slow down.\n\nNow set the magnet on the aluminum. It does not stick like it would to steel. The braking effect only occurs when the magnet and aluminum are moving relative to each other.\n\nAt high speeds this magnet-aluminum relationship builds up much like water causes a tire to hydroplane. This website wants to use this effect to build high speed railways: http://www.magplane.com
84144
You need to define "effect".  It also depends on the strength of the magnet, but if you're talking about something like a fridge magnet or something like that it's a very small fraction of an inch before the effect is negligible.
1084812
Iron is usually attracted to a magnet. If a bar of iron is magnetized, One end of the bar will attract one pole of the magnet, and repel the other pole of the magnet. \nCopper, nickel, and zinc are not magnetic. They neither attract or repel a magnet, and they cannot be magnetized.
179802
If you are looking for the maximum service temperature for a NdFeB magnet it is 150 degrees Celsius. \n\nIf you want to know the Curie Temperature for this magnet, which is the temperature at which the magnet will lose its ferromagnetism, it is 310 degrees Celsius. \n\nHere is a reference chart:\nhttp://www.magnetsales.com/Neo/Neoprops.htm#Physical