Astone is thrown upward at an angle. what happens to the horizontal component of its velocity as it rises? as it falls?

Rising or falling, it does not change.

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