When you increase the tension on a piece on a piece of wire the speed of waves on it increases but the wavelength stays constant what happens to the frequency of the waves as the tension on the wire is increased

The frequency increases because the tension of the wire increases

The magnets would be | n s | and | s n|

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