A wheel has a constant angular acceleration of 1.9 rad/s2. During a certain 7.0 s interval, it turns through an angle of 63 rad. Assuming that the wheel started from rest, how long had it been in motion before the start of the 7.0 s interval?

i think it would be 5

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.