Simple and complex machines

1. Simple and Complex Machines

2. Agenda
 Simple Machine
 Lever
 Screw
 Wheel- and- Axle
 Inclined plane
 Pulley
 Wedge
 Application of simple machines in a complex
machine

3. What are Simple Machines?
 machines with few or no moving parts.
 make work easier.
 use energy to work.
 change the direction of a force such a push or pull.

4. Types of Simple Machines
There are 6 simple machines.
They are:
1. Lever
2. Screw
3. Wheel- and- Axle
4. Inclined Plane
5. Pulley
6. Wedge

5. Lever
A lever is a straight rod that rotates around the fulcrum. There are 3
classes of levers representing variations in the relative locations of
the
fulcrum, the load and the effort.
Class-1
Here fulcrum is located between the effort & the load.
Examples of class-1 lever: Pliers, See-saw

6. Class-2
Here Load is located between the effort and the fulcrum.
An example of class-2 lever :Wheelbarrow

7. Class-3
Here Effort is located between the Load & the Fulcrum.
Examples of Class-3 lever: Human Arm lifting a Load, Tweezers

8. Screw
A screw is a thin rod with edges ,or threads that curve around it.
Turning a screw produces a force that can push the screw into wood or
tighten it against a nut. They are also used on jars and other
containers so that lids close tightly.
Types of screw
• Lag bolt:
A lag bolt is actually a screw that is very large and
only partly threaded. The head is square and needs to
be turned with a wrench rather than a screwdriver.
The lag bolt is used when a standard wood screw simply
isn't strong enough. It will probably be the largest
screw you'll find in your local hardware store .

9.  Wood Screws:
The standard wood screw is used to secure one piece of wood to
another. Screws with a rounded head are generally preferred for
thinner pieces of wood. Screws with a flat or oval-shaped head are a
better choice when you will be counter sinking the screw for a more
decorative appearance.
 Brass Screws:
Brass screws are essentially just wood screws that are made from
brass instead of steel. They are preferable in some cases because they
don't rust. Brass screws also add an aesthetic appeal that may be lost
when using steel screws.

10.  Security Screw:
Security screws feature specially shaped heads that allow them to be
inserted with a flat-blade screw driver. This special shape features a
slot designed in such a way that the screwdriver can grip it only when
turning the screw clockwise. The security part of this screw is in the
fact that since the screwdriver cannot grip it for turning counter
clockwise, the screw cannot be removed.

11. Wheel- and- Axle
Wheel and axle work together to make a simple machine. It is a wheel that
turns around a rod, called an axle that is fixed to the center of a wheel. A
wheel and axle can help move things faster or more easily, and also help
things turn. Heavy things can be difficult to push across a surface and can
require a lot of force. But, if you add wheels to the bottom, it becomes
much easier. When the axle is turned, the wheel moves a greater distance
than the axle, but less force is needed to move it.
Examples: A steering wheel in a car, Ferris wheels, doorknob, skateboard.

12. Inclined Plane
An inclined plane is a flat surface that is raised at one end. It takes
less force to move an object up along an inclined plane than it does to
lift it straight up.
Examples : Ramps, sloping roads

13. Pulley
A pulley is a simple machine that has a rope or cable that goes over an wheel.
A pulley helps people lift things up with much smaller forces. By pulling down
on one end of the rope, a person can lift an object attached to the other end.
The length of the string used to lift the pulley determines how much force is
needed.
Examples : Flag poles, crane, blinds , elevator, fishing
rod

14. Types of pulleys
 Fixed: A fixed pulley is fastened to one spot, and does not
move around. It provides no gain in force, distance or
speed, but it changes the direction of the force which means
the force is equal on both sides of the pulley and there is no
multiplication of force. Examples of fixed pulleys can be seen
on flag poles, drapes, or on a sail mast.
 Movable: A movable pulley moves along a rope or wire. It
provides a gain in force. A movable pulley is used to multiply
forces. If one end of the rope is anchored, pulling on the
other end of the rope will apply a doubled force to the
object attached to the pulley.
 Compound: A compound pulley, also called a block and
tackle, is a combination of a fixed and a movable pulley that
means several pulleys are mounted on each axle. This type of
pulley changes direction, and yields a gain in force at the
same time.

15. Wedge
A wedge is a piece of material that narrows to a thin edge. Wedges are
used to split things. The purpose or advantage of the wedge is to change
the direction of the applied force. Pushing the wedge in one direction
creates a force in sideways direction.
Example : Axe, knife , chisel, doorstop, saw, hammer, bulldozer, zipper,
scissors, fork, bow of a boat or ship

16. Complex machines
Simple machines can be combined to create complex machines.
Complex machines can be as small as a mechanical watch or as large
as a construction crane. Complex machines are also called compound
machines. Two or more simple machines work together to form a
complex machine. Compound machines can do more difficult jobs
than simple machines alone.
Examples of complex machines are:
Bicycle, wheel barrow, garden hoe , stapler, car jack ,crane , tow
truck, bicycle, can opener, lawn mower

17. Simple machines used in complex machines :
Compound Machine Simple Machine
Wheel and axle
Lever
Wheel barrow
Wedge
Lever
Garden hoe / Stapler
Wedge
Screw
Car Jack
Lever
Pulley
Crane / Tow truck

18. Compound Machine Simple Machine
Wheel and axle
Pulley
Lever
Screw
Bicycle
Wheel and axle
Wedge
Lever
Can opener
Wheel and axle
Screw
Lever
Wedge
Lawn Mower

19. A wheelbarrow’s long handles act as levers, and it rolls on a wheel
which acts as wheel and axle.
A Garden hoe is made up of a lever and a wedge. The handle of the
hoe is a lever, while the blade that cuts into the ground is a wedge.
A Stapler is made up of two Simple Machines, Wedge and Lever. The
staples in a stapler are wedges because they pierce through papers.
The top arm of the stapler is a Lever, it has a fulcrum or a pivot point,
which allows the top of the stapler to move up and down. When you put
energy on this lever, it transfers energy into a staple, which staples
the paper.
A Bicycle is a compound machine. Screws are used to hold the pieces
together and the seat adjustment is a screw. The wheels and pedals
each form a separate wheel and axle system. The pedals are attached
to a lever that turns a pulley. The brakes and brake handles are levers.
Can Opener is made up of 3 simple machines. First is the wheel and
axle which is the handle, when you turn the handle energy transfers to
the wedge which opens the can. Second is the wedge, the thing that
slices open the can is the wedge. Lastly is the lever, the arms of the
can opener are the levers. These two levers open and close on one
fulcrum to grip and help open the can.

20. References & Acknowledgements
 www.goggle.com
 www.wikipedia.com
 www.school.enboline.com

21. Prepared By:
Thomas