Sliding along
When an object slides past another, friction slows it down. You can test this with two sheets of sandpaper. If you try to slide their sanded sides over each other, you will find that friction make it hard work. If you turn the sheets over, the smooth side make the job easier. With slippery surfaces, such as ice or snow, there is so little friction that things slide along very fast. This helps skiers and bobsleighers to reach speeds over 200 km/h (125 mph).