What is a race car's average velocity if it completes one
lap around a 500 meter track in 10
seconds?

probably not if net force is zero

i already answered it by 34/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.