1. SIMPLE
MACHINES

2. PULLEY
A pulley is a wheel with a groove along its edge for
holding a rope or cable. It is a simple machine that helps change
the direction and point of application of a pulling force. Pulleys
are usually used in sets designed to reduce the amount of force
needed to lift a load. The magnitude of the force is reduced, but it
must act through a longer distance. Consequently, the amount of
work necessary for the load to reach a particular height is the
same as the amount of work needed without the pulleys.
Pulleys can be found in many different applications
around us. Not only are they used for the obvious lifting of objects,
such as by cranes, but they are also used in modern automobiles
and airplanes. Pulleys are also essential for most machines in
some form or other.

3. EXAMPLES OF PULLEYS
Block and Tackle
Pulley
Movable Pulley
Fixed Pulley

4. WEDGE
A piece of material, such as metal or wood, thick
at one edge and tapered to a thin edge at the other for
insertion in a narrow crevice, used for splitting, tightening,
securing, or levering.

5. EXAMPLES OF WEDGES
knife scissor axe

6. INCLINE PLANE
A plane set at an angle to the
horizontal, especially a simple machine used
to raise or lower a load by rolling or sliding.

7. EXAMPLE OF INCLINED PLANE

8. LEVER
A lever is a simple machine that makes work
easier for use; it involves moving a load around a pivot
using a force. Many of our basic tools use levers, including
scissors (2 class 1 levers), pliers (2 class 1 levers), hammer
claws (a single class 2 lever), nut crackers (2 class 2 levers),
and tongs (2 class 3 levers).

9. EXAMPLES OF LEVER