sentences: friction occurs when two object 's surfaces move 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 smoothness of a bottom increases, slip on the moving preposition will decrease & wood has a smooth surface & carpet has a rough surface -> 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  slip on the moving preposition glands when it is moving from the steel bottom to the wood bottom & as the friction increases, friction will decrease the speed of the object more -> the speed of the moving object on the carpet will be decreased more than the moving objects on the wood surface