SIMPLE MACHINES-PRINCIPLE
OF LEVERAGE
I-Ching Lee
Hao-Ting Kang
Wei Ling Zheng
CONNECTION
Our topic, “Simple Machines- Principle of Leverage” is
related to the lecture on 10/04/2010, “RotationTorque”– moments of the force acting in a clockwise
direction= moments of the force acting in a
counterclockwise direction.
On10/13/2010 , “Power and Efficiency.” – both our
topic and the lecture are based on work and used the
same equation:
Work = F  d
DISCOVERY
Archimedes, who was born in 287
BC, 212 BC, spent a huge amount
of time studying simple machines.
He explained the principle of
leverage and torque.
“Give me a place to stand, and I shall move the earth with a
lever”– Archimedes
WHAT IS PRINCIPLE OF LEVERAGE??
“Leverage is defined as a small force placed in a strategic place that
can bring extraordinary movement. It is a mechanical form of the
principle of multiplication.”
Principle of Leverage has been found
by experiment where two forces are
acting equally in opposite directions.
F load=F effort
(Load)(Load Arm)=(Effort)(Effort Arm)
Also, this experiment shown that when two unequal forces were
acting in opposite direction will bring about equilibrium when
moment of a force is equal to other moment of a force. This
established when the sum of the moments of the force acting in a
clockwise direction is equal to the sum of the moments of the force
acting in a counterclockwise direction.
The principle of leverage can divided into three classes
by the locations of the load, effort with respect to the
fulcrum.
CLASS I
Fulcrum is located between Load and Effort.
The length of the effort arm can be greater,
less than, or equal to the length of the load
arm.
We can use less effort or more effort into
the lever depends on the length of the
arms.
Examples: Scissors, Pliers, SeeSaw, Oars on a Boat
CLASS II
Load is located between Effort and Fulcrum.
The length of Effort Arm is greater than
the length of Load Arm; therefore, we use
the least effort in the Class II lever.
Examples: Door, Nut Cracker, Bottle
Opener
CLASS III
Effort is located between Load and Fulcrum.
The length of the Load Arm is greater than the length of the
Effort Arm; therefore, we use the most effort in Class III lever.
Examples: Stapler, Hockey Stick,
Broom, Tweezers, Mousetrap
INSIGHT
After learning this topic– Simple Machines- Principle of Leverage,
we realized that there are numerous of everyday objects
involving the idea of simple machines – principle of leverage. For
example, where the handle locate on the door make us easy to
push it, and we can lift heavy objects with less force.
Many inventions of tools are based on the theory of simple
machines, which make our daily life more convenience.
WORK CITED:
So, By Doing. "The Principle of Leverage And How To Use It In
Our Life." Ready To Be Rich - Business, Investments and
Personal Finance. 17 May 2008. Web. 13 Nov. 2010.
<http://fitzvillafuerte.com/the-principle-of-leverage-and-how-touse-it-in-our-life.html>.
Kurtus, Ron. "Lever Is a Simple Machine - Succeed in
Understanding Physics: School for Champions." School for
Champions: Online Lessons for Those Seeking Success. 26 June
2008. Web. 13 Nov. 2010. <http://www.school-forchampions.com/science/machines_lever.htm>.
"Discovery: Levers." Pitsco Education Online Store. Web. 13 Nov.
2010.
<http://shop.pitsco.com/content/item.aspx?CategoryID=114&ap=1
&art=15&bhcp=1>.