Magnetic Levitation question

[LazerFazer]

Hi all,

 

This isn't a homework problem as such, but it's a Lab question instead.

 

First off, is it possible, using a solenoid with current passing through it, to levitate a second magnet?

 

If so, how do you calculate the force of magnetic repulsion between two magnets?

 

EDIT: OK, I found out it IS possible to do what I wanted. Now, I would appreciate it if somebody could tell me how to determine the force of attraction/repulsion between the magnet and the solenoid?

 

Thanks in advance,

LazerFazer

[RyanJ]

Hi all' date='

 

This isn't a homework problem as such, but it's a Lab question instead.

 

First off, is it possible, using a solenoid with current passing through it, to levitate a second magnet?

 

If so, how do you calculate the force of magnetic repulsion between two magnets?

 

EDIT: OK, I found out it IS possible to do what I wanted. Now, I would appreciate it if somebody could tell me how to determine the force of attraction/repulsion between the magnet and the solenoid?

 

Thanks in advance,

LazerFazer[/quote']

 

An interesting problem.

 

Could you not put them in a force guage (e.g. a piece of metal above the first and below the second) and then hook this up to a force meter to test their repulsive power?

 

Cheers,

 

Ryan Jones

[LazerFazer]

RyanJ, that would work, but I guess I didn't give enough information as to the entire problem.

 

You see, I'm trying to determine the strength of a cylindrical magnet using a solenoid. The way I'll do this is by suspending the solenoid above the cylindrical magnet, hooking it up to a variable voltage power supply and an ammeter, and turning it on. Then, I'll increase the voltage and thus the current (since R will stay relatively constant) until the magnet is 'sucked up' into the solenoid. At the instant the magnet is pulled off the surface, the Magnetic force (Fb) will be equal to the gravitational force (Fg). So, by setting Fg=mg, and setting the two forces equal to each other, I'll be able to calculate the value of the B-field of the magnet. This is possible because I can calculate the strength of the solenoid B-field because I know N,L, and I, and therefore can use B=(MEW-zero)(NI/L).

 

So, in summary, I would appreciate a formula relating the magnetic force to the two magnetic fields. I found somewhere that it follows the same format as the gravitation force, i.e. Fb=(B1*B2)/(MEW*r^2) Is this in any way correct?

 

Thanks,

LazerFazer