°

Here's a mnemonic phrase that serves to recall the names of the different types of machine found in universal mechanics, sent in (9/00) by Barbara D. Marin:

"I Like Playing Soccer With William."

(Inclined plane, Lever, Pulley, Screw, Wedge, Wheel and axle)

A machine is a contrivance or mechanism by means of which a force, applied at one part of the machine, is transmitted to another part, in order to secure mechanical advantage for some particular purpose. There are basically six types of machine:

The inclined plane
- used for raising a load by means of a smaller applied force. Mechanical advantage is resisted by some friction.
The lever
- involves a load, a fulcrum and an applied force. Often just a uniform bar.
The pulley
- In simplest form it changes the direction of a force acting along a cord or rope.
The screw
- constructed using the principle of the inclined plane set on a cylindrical or conical surface. A screw-jack lifts heavy weights. Many screw-threads are in everyday use.
The wedge
- a double inclined plane. Mechanical advantage is considerably resisted by friction.
The wheel and axle
- Used to draw water from a well etc. by ropes attached to a large wheel and to a smaller axle. A differential wheel and axle has two-part axle sizes and gains considerable mechanical advantage.