in a magnetic screwdriver or kitchen magnet
magnets have negative and positive charges
[object Object]
If you place a second object between two magnets, it may interact with the magnetic field of the magnets. Depending on the properties of the object and the strength of the magnets, it can either be attracted to or repelled by the magnets. The alignment, distance, and orientation of the objects will also affect the interaction.
because magnets attracts any object that is metallic or has metal in them
It is not a question of how many magnets you need, one would do; but how strong the field is and how strongly it attracts the 400 pound object.
To use strong magnets for hanging objects securely, you can attach a strong magnet to the object you want to hang and then place another strong magnet on the surface where you want to hang the object. The magnets will attract each other, creating a secure hold for the object. Make sure the magnets are strong enough to support the weight of the object.
magnets repel magnets. a north repels north, south repels south and north attracts south poles
I don't knwo
If you hold two magnets in your hand one below the other so that the north side of one magnet is facing north of the other and vice-versa, then place a metallic entity between these two magnets then it will appear to float provided distance between magnets and their force is equal.
magnets have potential energies associated with them and whatever object they are interacting with (must have charge to interact...). this energy does work as the force is exerted on said object, the direction being dependent on the charge. so yeah magnets can pull stuff
diamagnetic
just by attaching the magnets to the the weakest part of the object to hold together the whole thing