(Explanation based on vectors) Suppose you don't know A and B. But you do know A+B=C and A-B=D, can you figure out A and B (vectors).

568.98

explanation:

its math

massxgravity x heght=weightxheight= pe

4900=490xh

h=10

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.