What can parents do to ensure the safety of their child in a sport. (site 1)what can parents do to ensure the safety of their child in a sport. (site 1)

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

Decrease the surface area of the object and also decrease the concentration which will allow the particles to collide faster