If Galileo was about to drop a 5kg cannonball from 12m high, how much PE would the cannonball have?

it is a negative acceleration

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.