Magnet Force Q: Repel/Attract at 3cm Distance

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The discussion focuses on the interaction between magnets and a magnetic substance, referred to as substance Q, at a distance of 3cm. It explores whether an identical magnet repelling substance Q will experience a force of -X, equal in magnitude but opposite in direction to the force experienced by a magnet attracting substance Q. The response clarifies that the force depends on the field gradient from substance Q, which is consistent at that distance if the field is isotropic. Additionally, it emphasizes that both magnets must have identical dimensions and orientations for the forces to be equal. Proper alignment and positioning are crucial for achieving the desired smooth movement in the machine being built.
Green Zach
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Ok so, i think this is kinda a basic question but here goes. I am building a machine that uses magnets and desperately need to eliminate a zero point so the movement will be smooth so what i need to know is if you have a magnet being attracted to substance Q and the magnet has a 3cm distance from substance Q and is being attracted to substance Q at a force of X then will an identical magnet repelling substance Q at a distance of 3cm experience a force of -X? or is their a distance ratio? Of course substance Q is magnetic with + and - poles. any info or help would be greatly appreciated. :smile:
 
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Could you draw a picture? That description is really confusing.

Is this it? M -- Q -- m Where M is the first "attractive" magnet and m is the 2nd, "repelling" one.

My initial guess would be that you are right.
 
Green Zach said:
Ok so, i think this is kinda a basic question but here goes. I am building a machine that uses magnets and desperately need to eliminate a zero point so the movement will be smooth so what i need to know is if you have a magnet being attracted to substance Q and the magnet has a 3cm distance from substance Q and is being attracted to substance Q at a force of X then will an identical magnet repelling substance Q at a distance of 3cm experience a force of -X? or is their a distance ratio? Of course substance Q is magnetic with + and - poles. any info or help would be greatly appreciated. :smile:
The force comes from the field gradient due to Q at the position of the magnet as well as the pole strength, length and orientation of the magnet. If the field due to Q is isotropic, then the gradient will be the same at all positions 3cm away from Q. The important thing then is to get the second magnet to have the exact same dimensions and the exact opposite orientation to the first. I assume that Q is fixed rigidly and thus, can not move.
 
Gokul43201 said:
The force comes from the field gradient due to Q at the position of the magnet as well as the pole strength, length and orientation of the magnet. If the field due to Q is isotropic, then the gradient will be the same at all positions 3cm away from Q. The important thing then is to get the second magnet to have the exact same dimensions and the exact opposite orientation to the first. I assume that Q is fixed rigidly and thus, can not move.

so as long as both magnets A and B are identical than both + and - forces should be identical?
 
Yes, so long as A and B are placed in virtually identical positions.
 

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