two objects with equal mass are collide. calculate the velocity after the collision if ball red is 10m/s and ball blue is 20m/s​

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.