LeverLever

A A leverlever is a bar that is free to turn, is a bar that is free to turn, about a fixed point.about a fixed point.

FulcrumFulcrum

• The fixed point of a lever is called the fulcrum.

Effort armEffort arm

• The part of the lever on which the effort force is applied is called the effort arm.

Resistance ArmResistance Arm

• The part of the lever that exerts the resistance force is called the resistance arm.

Mechanical Advantage (MA)Mechanical Advantage (MA)

• Length of the effort arm is the distance from the fulcrum to the point where effort force is applied.

• Length of the resistance arm is the distance from the fulcrum to the point where effort force is applied.

MAMA

• MA=Length of effort arm/length of resistance arm

Different type or classes of Different type or classes of leverslevers

• First class

• Second class

• Third class

A pulleyA pulley

• Is a grooved wheel with a rope or a chain running along the groove.

Fixed pulleyFixed pulley

• Is attached to something that doesn’t move,such as ceiling, wall, or tree.

A moveable pulleyA moveable pulley

• Is attached to the object being moved.

• Unlike the fixed pulley, a moveable pulley does multiply the effort force. And it has greater MA.

A wheel and axelA wheel and axel

• Is a simple machine consisting of two wheels of different sizes that rotate together.