PHYSICS-2Que&Ans1.how do you prove that friction produces heat energy?

PHYSICS-2Que&Ans1.how do you prove that friction produces heat energy?2.why do sport`s man use spikes?3.How do you reduce efect of friction?4.write about fluied friction, how fluied  friction can controles?5.Define how area of contact increases pressure?6.Explain any two kind of frictional forces?