Lever, simple machine consisting of a rigid bar that rotates about a fixed point, called a fulcrum. Levers affect the effort, or force, needed to do a certain amount of work, and are used to lift heavy objects. To move an object with a lever, force is applied to one end of the lever, and the object to be moved (referred to as the resistance or load) is usually located at the other end of the lever, with the fulcrum somewhere between the two. By varying the distances between the force and the fulcrum and between the load and the fulcrum, the amount of effort needed to move the load can be decreased, making the job easier. Physicists classify the lever as one of the four simple machines used to do work. (The other three are the pulley, the wheel and axle, and the inclined plane.) Work is defined in physics as the result of a force, such as a person lifting, that moves an object over a distance. A common example of a lever is the seesaw. The human arm is also a lever, where the elbow is the fulcrum and the muscles apply the force.

1. LEVERS AND ITS TYPES
Prepared By
Ronnith
Nandy

2. -
Levers are one of basic tools that were probably used in prehistoric times. It
is assumed that in ancient Egypt, constructors used the lever to move and
uplift obelisks weighing more than 100 tons.
Lever is a simple machine that makes
work easier to use; it involves moving a
load around a pivot using a minimum
force.
A lever amplifies an input force to
provide a greater output force,which
is said to provide leverage. The levers
are used to lift heavy weight with
least amount of effort.
LEVERS

3. -
Lever – A bar that is free to pivot
around a center point (Changes
direction and/or amount of force).
Fulcrum – The fixed point around
which a lever pivots (fulcrums can
take many shapes).
Effort Force – The force applied
to a machine to cause motion of an
object. (Measured in Newton N)
Resistance Force – The force
exerted by an object due to gravity
or friction. (Measured in Newton N)
Resistance Arm – The part of the
lever on which the resistance force is
exerted.
Effort Arm – The part of the
lever to which the effort force is
applied.
LEVER SYSTEM

4. -PRINCIPLE OF LEVER
The lever is based on the
principle of lever stating that:
"The force pushing upward at
one end of a lever is equal to the
force pushing downward at the
other end times the ratio of the
distance of the two forces from
the pivot point.
The figure illustrates the
principle of the lever.

5. -EXAMPLES OF LEVER IN EVERYDAY
LIFE

6. -
In a Class 1 Lever, the pivot
(fulcrum) is between the effort
and the load. In an off-center
type one lever (like a pliers), the
load is larger than the effort, but
is moved through a smaller
distance.
FIRST CLASS LEVER

7. -FIRST CLASS LEVER
EXAMPLE IN EVERYDAY LIFE

8. -SECOND-CLASS LEVERS
Second-class levers have the load between
the effort and the fulcrum. A wheelbarrow
is a second-class lever. The wheel’s axle is
the fulcrum, the handles take the effort, and
the load is placed between them. The effort
always travels a greater distance and is less
than the load.

9. -SECOND CLASS LEVER
EXAMPLE IN EVERYDAY LIFE

10. -THIRD-CLASS LEVERS
Third-class levers have the effort placed
between the load and the fulcrum. The effort
always travels a shorter distance and must be
greater than the load. A hammer acts as a
third-class lever when it is used to drive in a
nail: the fulcrum is the wrist, the effort is
applied through the hand, and the load is the
resistance of the wood.

11. -
THIRD CLASS LEVER
EXAMPLE IN EVERYDAY LIFE

12. -
THANK YOU