mrs. knight drops her briefcase. when the briefcase lands on the floor, what is the reaction force to the action force of the briefcase on the floor?

The force of the floor on the briefcase

Explanation:

The briefcase hits the floor and stops the falling which is reacting to the briefcase that was falling and hits the floor.

The falling briefcase would be the action force because it is moving downward

and

The reaction force would be the floor because it will react on the briefcase.

Hope this Helps

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.