Question about magnetic attraction relationships.

[nwman]

Hello all,

I could spend hours trying to look this up but I thought I would just ask first. I have been wondering how to express the relationship of work in terms of why its easier to pull to magnets apart by sliding them apart at 90 degrees from the angle of attraction then it is to pull them straight apart at the same angle of attraction. The amount of work preformed to pull them apart in any direction should be the same? Should it not?

This is what I think I know:

Work = force x distance

1) the force needed to pull straight apart is greater then the force needed to pull apart at 90 degrees.

2) The distance needed to pull apart by sliding them at a 90 degree angle is longer then the distance needed to pull them straight apart?

Since the the forces vary then the distance that is needed to pull them apart should vary in the same proportion to make the equations match.

To me it just seem the distances are nearly the same but the force needed is greatly different. If true then the equations would not match and there is a hole which one can look into. 


So to really state me question:

Can someone point me in the direction to where I can find the formulas to calculate the work relationships between pulling magnets apart at different angles?

Thanks,  Tim

[gyulasun]

Hi Tim,

Maybe this thread here brings you closer to solving some questions, though not fully energywise :
http://www.overunity.com/index.php/topic,697.msg47687.html

rgds,  Gyula

[nwman]

I haven't given it enough thought yet to be able to wrap my brain around this theory but below is a simple expression of the concepts I'm thinking of. If you want I can explain it but I think its fairly obvious. I'm sure it don't work but I thought I would just throw it out there.

Tim

[Low-Q]

Hi,

Interesting view you got. I think you must use equal amount of energy to slide as you use to pull two magnets apart. In fact, sliding takes more energy to perform as you have great friction between the magnets. But lets say the magnets is 1mm apart so no friction is present when sliding, the same energy is used to take those magnets apart - sliding or pulling. It all depends on the shape. Two disc magnets are easier to slide apart as the surface is great and length is short. If you use two long and thin bar magnets, they would probably felt equally if you slided or pulled them apart.

Br.

Vidar

[Mr.Entropy]

The amount of work preformed to pull them apart in any direction should be the same? Should it not?

Yes, it's the same

To me it just seem the distances are nearly the same but the force needed is greatly different. If true then the equations would not match and there is a hole which one can look into. 

To get the energy, you have to add up force*distance for each little bit of the path along which you separate the magnets.

When you pull them straight apart, you must initally apply a much greater force, but this great force only needs to be applied over a very short distance before it drops off and the magnets can be pulled the rest of the way apart with ease.

When you slide them apart, it takes much less force initially, but this force must be applied over a much longer path before the magnets are separated enough for it to drop off.