A 15.0-lb block rests on the floor. (a) What force does the floor exert on the block? (b) If a rope is tied to the
block and run vertically over a pulley, and the other end is attached to a free-hanging 10.0-lb weight, what
is the force exerted by the floor on the 15.0-lb block? (c) If we replace the 10.0-lb weight in part (b) with a
20.0-lb weight, what is the force exerted by the floor on the 15.0-lb block?
what is the speed of a softball that travels 20m in 2secs
speed = 20/2 = 10 m/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.