friction occurs when two object 's surfaces move against each other & as roughness of a surface increases , friction will increase ->  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 & 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 & 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