This document discusses simple machines, including the lever. It defines a lever as a bar that pivots around a fixed point called a fulcrum. The document explains that the work done by a person should equal the work done by a machine, using the equation Work = Force x Distance. It describes how machines make work easier by allowing smaller forces to produce larger forces. Levers are classified into three classes based on the position of the fulcrum. Many common tools and devices use levers to multiply force, including seesaws, wheelbarrows, and scissors. Levers are essential in daily life and make many tasks possible.

1. THE PRESENTATION

2. In simple way
It is a kind of simple machine
Every machine is a combination of
Different simple machines

3. Incline plane
lever
Screw
pully
Wedge
Wheel & axel

4. Definition: a lever is a bar that is free to turn
around a fixed point, called a fulcrum

5. ‘WORK’
Remember that Work = Force x Distance
So… this same equation applies to the work done by
machines.
Work done by you should be equal to the work done by
the machine!
The machine does the same amount of work, it just
makes it easier for you!

6. W (by you) = W (by machine)
Fe x de = Fr x dr
resistance
force
effort distance
resistance
distance
THIS IS A TYPE
OF LEVER!!!

7. Effort force = the force YOU put in
Resistance force = the force of the machine

8. Compares your force with
the force of the
machine
Which one should be
bigger?
The force of the
machine!
So…the MA measures
how many times the
force of the machine
(resistance force) is
greater than your force
(effort force)

9. Compare the
resistance
force to the
effort force…
Fr / Fe

10. 1st
Class
Fulcrum is in
the middle of
bar

11. Examples of 1st
class levers:
Seesaw crowbar scissors

12. 2nd
Class
Fulcrum is on
one end

13. Examples of 2nd
class levers:
nut cracker bottle opener wheel barrow

14. 3rd
class
Fulcrum on
one end

15. Examples of 3rd
class levers:
Tennis bat golf club etc.

18. Uses
There is a large no. of
uses of lever , such as
Scissor
Nut craccker
Bottle opener
Wheel borrow
Cricket bat
See-saw etc.

19. In our daily life the applications of lever is
all around us, So we can say that life
without lever is very difficult and some
times its impossible