Why is it important to know the velocity of an object, not just its speed? speed is only useful for fast-moving objects. velocity also tells you direction of motion. speed is always an average. velocity tells you the average speed.

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.