Nature of Machines Machines are any device that transfer a force from one place to another Nutcracker ramp engine All complicated machines contain many small simple machines ID: 447815
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Slide1
Simple MachinesSlide2
Nature of Machines
Machines are any device that transfer a
force
from one
place
to
another
.
Nutcracker, ramp, engine
All
complicated
machines contain many small
simple
machines.
Simple Machines
– the basic devices for transferring mechanical forces in all machinery.Slide3
Action of Machines
Effort Force
– the force
you apply
to the machine.
Effort Distance
– The distance the
effort force
acts through.
Resistance Force
–
T
he force the
machine applies
to some objects.
Opposite
the effort force.
Resistance Distance
– The distance through which the
resistance force acts
.Slide4
Effort Force
Effort Distance
Resistance Distance
Resistance Force
FulcrumSlide5
Laws of Machines
Under
ideal
conditions, the amount of
work
put
into
a machine is equal to the amount of work the machine
does.Ideal conditions refer to NO HEAT, produced by friction, and
NO AIR RESISTANCE, created when the machine is used.Real machines do create friction and therefore creates
less energy than it takes in.Slide6
Purpose of Machines
Machines make work seem
easier
and
faster
.
Multiply a
forceChange the direction
of a forceMultiply a distanceMultiply speedSlide7
Types of Simple Machines
There are
six
types of simple machines
Compound
machines are made from one or more of these six simple machines.
Lever
– a bar that rotates around a fixed point,
fulcrum.
FulcrumSlide8
3 Classes of Levers
First
Class Lever
Fulcrum
is between the
input force/Effort
and the
load
.Ex. Claw end of a hammerSecond Class Lever
Load is between the fulcrum and the input force/effort
Ex. A can openerThird Class LeverInput force/effort
is between the fulcrum and the load.Ex. Your arm lifting a weightSlide9
Types of Levers
Label the Effort (
E
), Resistance (
R
), and Fulcrum (
F
) in each of the pictures and then
determine the type of lever each represents.
E
E
E
E
F
F
F
F
R
R
R
R
1
st
Class
2
nd
Class
2
nd
Class
3
rd
ClassSlide10
2
nd
Class
1
st
Class
1
st
Class
3
rd
Class
E
E
E
E
F
F
F
F
R
R
R
RSlide11
Types of Simple Machines
Inclined Plane
– A flat surface that slants up at an angle.
Ex. A rampSlide12
Types of Simple Machines
Wedge
– two inclined planes placed back to back.
The
longer
and
thinner
the wedge is, the
less energy is required to do work.Ex. Knife, ax, razor blade.Slide13
Types of Simple Machines
Screw
– an inclined plane that is wrapped around a cylinder
Rotates
with each turn moving it up or down
The
closer
the threads, or ridges, the
easier the work is.Ex. A jar lid, soda bottle cap, boltsSlide14
Types of Simple Machines
Pulley
– A grooved wheel that holds a rope or
c
able.
It can change either the
direction
or the amount of an
effort force.2 Types:Fixed
Movable Slide15
1.
Fixed
–
attached to a stationary object.
2.
Movable
–
not attached to a stationary objectSlide16
Types of Simple Machines
Wheel and Axle
– two circular object of different sizes rotating in a circle.
Two different sized wheels:
Axle
– the smaller wheel
Wheel
– turns about the smaller axle.Slide17
Identify the Simple Machine
Pulley
Wedge
Lever
Wheel and Axle
Screw
Inclined PlaneSlide18
Identify the Simple Machine
Pulley
Lever
Inclined Plane
Wheel
a
nd
Axle
Wedge
Wheel and
Axle
Lever
Lever
Screw