WEDGES                             

       Wedges are devices that are thick at one end and tapers to a thin edge at the other end. A wedge is kind of like an inclined plane except that it can move. The longer and thinner the wedge is, the less input force needed to do the same amount of work. Some wedges are axes, zippers, door stoppers and even your two front teeth of incisors.

      
      Axes are wedges because of the sharp part that is used to cut things . When you use an ax to cut wood, you apply input force to the handle. The handle exerts that force to the thick part of the wedge. The force pushes the wedge into the wood. The wedge exerts output force on the wood causing it to split.

      If you try to open or close a zipper on your own it would be really hard. That is because you don't have enough force by yourself. When you close a zipper, the little wedges inside the zipper pull multiplies your input force. That causes the zipper to open or close.

         Incisors are shaped like wedges and act as wedges. When you bite down on food, such as an apple or a pear, your incisors have enough force to break the food in half. Incisors biting down on wood are kind of like axes when they split up wood.