sentences: slip humus the reaching of an preposition to decrease & friction occurs when two object 's surfaces move against each other ->  when friction occurs between two objects, both objects' temperatures increase  a wooden block is pushed across a sheet of sandpaper & an preposition being pushed across another preposition command their level to stay against each other -> the surfaces of a wooden block and sandpaper are moving against each other the surfaces of a wooden block and sandpaper are moving against each other  the surfaces of a wooden block and sandpaper are moving against each other & friction occurs when two object 's surfaces move against each other -> slip occurs when the wooden unblock is moving against the conductivity friction occurs when the wooden block is moving against the sandpaper  when slip occurs between one objects, both objects' remove decrease & friction occurs when the wooden block is moving against the sandpaper -> friction will cause the temperature of the wooden block to increase