A magnet can do work in the same sense that a rock can do work, or water can do work. The energy is not in the magnet or the rock or the water, it is in it's releationship to other objects. A magnet in a magnetic field is no more of a mystery than a rock or bucket of water in a gravitational field.
Take a universe empty except for 2 boulders (100Kg, say). They are right next to each other. They have no potential enery (ignoring the E=mc^2 engery) Now separate them by 100Km. The suddenly have energy due to their gravitational attraction. They will fall toward each other accelerating until the collide. Just before the collision they have no potential energy and all kinetic energy. How much energy? Exactly the same amount of energy it took to separate them.
You cannot create or destroy energy, you can only move it around. In a broad sense energy is what it takes to go from one configuration of matter to another. This can be either plus or minus, i.e. it might require energy input (lifting a boudler) or it might release energy (dropping a boulder) as you change the configuration. And changing it back again requires the same amout of energy with the opposite sign.
Bob
Take a universe empty except for 2 boulders (100Kg, say). They are right next to each other. They have no potential enery (ignoring the E=mc^2 engery) Now separate them by 100Km. The suddenly have energy due to their gravitational attraction. They will fall toward each other accelerating until the collide. Just before the collision they have no potential energy and all kinetic energy. How much energy? Exactly the same amount of energy it took to separate them.
You cannot create or destroy energy, you can only move it around. In a broad sense energy is what it takes to go from one configuration of matter to another. This can be either plus or minus, i.e. it might require energy input (lifting a boudler) or it might release energy (dropping a boulder) as you change the configuration. And changing it back again requires the same amout of energy with the opposite sign.
Bob