4.43. Wedge http://www.ck12.org
4.43 Wedge
- Describe a wedge.
- Explain how a wedge changes force to make work easier.
- Identify the mechanical advantage of a wedge.
A chisel is a very useful tool for carving wood, rocks, and other hard substances. This man is using a chisel to
remove large pieces of wood. A chisel is a type of machine called a wedge.
What Is a Wedge?
Awedgeis simple machine that consists of two inclined planes, giving it a thin end and thick end, as you can see in
theFigure4.85. A wedge is used to cut or split apart objects. Force is applied to the thick end of the wedge, and the
wedge, in turn, applies force to the object along both of its sloping sides. This force causes the object to split apart.
A knife is another example of a wedge. In theFigure4.86, a knife is being used to chop tough pecans. The job is
easy to do with the knife because of the wedge shape of the blade. The very thin edge of the blade easily enters and
cuts through the pecans. You can see other examples of wedges, as well as a history of the wedge, at the following
URL:
http://www.historyforkids.org/scienceforkids/physics/machines/wedge.htm
Mechanical Advantage of a Wedge
The mechanical advantage of a simple machine is the factor by which it multiplies the force applied to the machine.
It is the ratio of the output force to the input force. A wedge applies more force to the object (output force) than the
user applies to the wedge (input force), so the mechanical advantage of a wedge is greater than 1. A longer, thinner
wedge has a greater mechanical advantage than a shorter, wider wedge. With all wedges, the trade-off is that the