If you stand on a horizontal floor, a distance x directly in front of a vertical mirror, and the top of the mirror is level with the top of your head, what must be the minimum height of the mirror be, in order for you to be able to see your feet in the mirror

Answer///air resistance,drag;

Answer(a)   the matererials that are in contact, the two materials and the nature of their surfaces/// (b)/// the force pushing the two surfaces together, pushing the surfaces together causes the more of the asperities to come together and increases the surface area in contact with each other