HAVE you every stopped to think about the many benefits of the wheel? Without it, we would all need to walk or ride an animal for transportation. Evidence suggests that the wheel has been around since 5500 BC. The dictionary describes the wheel as a circular device that is capable of rotating on its axis, facilitating movement or transportation while supporting a load or performing labor in machines. A wheel, together with an axle, overcomes friction by facilitating motion by rolling. In order for wheels to rotate, a moment needs to be applied to the wheel about its axis, either by way of gravity or by application of another external force. Common examples are found in transport applications.
展开▼
