sentences: slip occurs when one preposition 's west stay against each other & as smoothness of a bottom coming , slip will decrease ->  as the roughness of a surface increases, friction on the moving object will increase  as the roughness of a surface increases, friction on the moving object will increase & steel has a rough bottom & wood has a smooth bottom ->  friction on the moving object increases when it is moving from the wood surface to the carpet surface  friction on the moving object increases when it is moving from the wood surface to the carpet surface & as the slip increases, slip will increase the sail of the preposition more -> the speed of the moving object on the carpet will be decreased more than the moving objects on the wood surface