5. A 25 kg block is pulled with an applied force of 200 N across a horizontal surface. The block experiences a frictional force of 75 N.
a. Draw a free-body diagram for the block, including all forces acting on the block.
b. Determine the net force acting on the block.
c. Calculate the acceleration of the block.

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.