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Force of magnets 
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#1
Oct2605, 01:38 AM

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Magnet A has twice the magnetic field strength of magnet B (at equal distance) at a certain distance and pulls on the magnet B with a force of 30N. Determine the force with which magnet B pulls magnet A.
Could someone help me. I'm just starting physics in hs. 


#2
Oct2605, 01:44 AM

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Do you have any reason to believe the forces will be different  i.e. Newton's law of action reaction does not apply?



#3
Oct2605, 01:48 AM

P: 12

thats probably correct. this is a basic question. i think it is getting at coulombs law.
i think the answer is 15N. not sure 


#4
Oct2605, 01:53 AM

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Force of magnets
If you're talking about magnets you're probably not dealing with Coulomb's law.
So, why do you think the answer is 15 N? 


#5
Oct2605, 01:58 AM

P: 12

well i'm not exactly sure. i'm looking in the chapter of magnetism in my book and i don't see any forumla's. its weird. i went back a chapter and found coulombs which deals with force=(k)(q1q2)/d^2.
i wasn't sure if it was right or now. if you could help me on a formula i could try and solve it. thanks jeff 


#6
Oct2605, 01:59 AM

P: 12

i think because magnet a is twice as strong, that magnet b is half of its strength.
also i forgot a few parts of the question that might help it has twice the magnetic field strength. 


#7
Oct2605, 02:56 AM

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I have no idea what equations your textbook shows but if you have none relating the pulling force of a magnet that should be a clue for you!
Remember Newton's Law that I mentioned earlier and think about this: If a magnet is twice as strong then not only it will it pull another with twice the force it will also be pulled with twice the force! 


#8
Oct2605, 11:44 AM

P: 12

so the answer is that since they are an equal distance away. that the force that a acts upon b is the same force that b acts upon a.
answer 30N? 


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