Question

what would happen if the soles of shoes & tyres of vehicles are not treaded?

Answer 1

They are treaded to increase friction between floor and us. if they are not treaded then it wont give us enough friction and we may fall .

Answer 2

shoes and tyres are treaded to increase friction .if they are not treaded friction between us or between the objects will be lost.so this may lead to skidding.that is the reason they are treaded