I understand the basics of magnetism; charge, fields, etc, but I don’t understand how a magnetic field can apply force seemingly forever.
For example, if I bring a magnet close to another magnet, that other magnet will eventually be drawn to the magnet in my hand, causing it to move. That kinetic energy “is caused by the magnetic attraction” but how?
If I keep my hand between two magnets, they will squeeze against my hand for seemingly forever. If I were to squeeze my own hand, I’ll get tired eventually from the exertion, but magnets don’t “get tired.” Are magnets somehow infinite energy machines? I’d assume they aren’t, but where is this energy coming from and why does it seem endless?
Edit: yes I understand the difference between “force” and “energy,” defining those terms doesn’t actually answer my question!
In: Physics
You need to put energy into the system to bring a magnet close to another repulsive one. That energy is then reversed when it pushes it away. Same goes for magnets that attract, except that you’re giving energy to the system when you’re pulling them apart.
For the scenario when you’re holding the magnet, there’s no energy to talk about at that moment. Yes there is a constant force, but nothing is accelerating. You’ll get tired because of the way our muscles work, not because there’s some sort od energy flow happening. It’s the same scenario as holding something heavy in your hands, gravity is constantly pulling it down and you feel like you have to use energy to fight it, while at the same time you could just put the object down onto a table and suddenly there’s no energy being wasted to hold it in place. Energy is only used when you’re moving an object away from an attractive force (gravity, magnet) or accelerating it.
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