The wedge is another simple machine and fundamental innovation in mechanical engineering. They have been used since prehistorical times for activities like splitting logs (axes) or rocks (chisels).
Wedges are defined as movable inclined planes that can be used to separate two objects (or portions thereof), lifting objects or holding them in place via the application of force to the wide end. The wedge's shape, therefore, converts one input force into perpendicular forces 90 degrees to the inclined surfaces.
The mechanical advantage achieved by any wedge is dependent on the ratio of its length to thickness. In other words wide, short wedges require more force but produce a quicker result than a long, low angled wedge.