Machines and Work Relationships
Machines
14-2
Lesson Objectives
•
I can describe what a machine is.
•
I can describe how a machine makes work easier
to do.
•
I can describe the relationship between force and
distance when using a machine.
•
S
o
l
a
s
t
t
i
m
e
w
e
s
a
w
t
h
a
t
t
h
e
a
m
o
u
n
t
o
f
w
o
r
k
y
o
u
d
o
d
e
p
e
n
d
s
o
n
a
f
o
r
c
e
b
e
i
n
g
u
s
e
d
t
o
m
o
v
e
a
n
o
b
j
e
c
t
a
c
e
r
t
a
i
n
d
i
s
t
a
n
c
e
.
T
h
e
f
a
s
t
e
r
y
o
u
a
c
c
o
m
p
l
i
s
h
i
t
,
t
h
e
m
o
r
e
p
o
w
e
r
t
h
e
r
e
i
s
!
Work and Power Lab
S
o
,
i
f
s
o
m
e
o
n
e
h
a
s
t
o
g
e
t
t
h
e
m
s
e
l
v
e
s
u
p
a
c
e
r
t
a
i
n
d
i
s
t
a
n
c
e
,
t
h
e
n
t
h
e
y
h
a
v
e
t
o
d
o
t
h
e
e
q
u
i
v
a
l
e
n
t
a
m
o
u
n
t
o
f
w
o
r
k
T
h
e
h
e
i
g
h
t
o
f
t
h
i
s
s
t
a
i
r
c
a
s
e
i
s
t
h
e
d
i
s
t
a
n
c
e
T
h
e
e
f
f
o
r
t
H
o
m
e
r
n
e
e
d
s
t
o
j
u
m
p
u
p
i
s
t
h
e
f
o
r
c
e
!
T
h
e
f
f
o
o
r
r
c
c
e
e
o
o
f
f
t
t
h
h
e
e
j
j
u
u
m
m
p
p
x
h
h
e
e
i
i
g
g
h
h
t
t
o
o
f
f
t
t
h
h
e
e
s
s
t
t
a
a
i
i
r
r
s
s
i
s
t
h
e
w
o
r
k
h
o
m
e
r
a
c
c
o
m
p
l
i
s
h
e
d
!
I
t
d
o
e
s
n
’
t
m
a
t
t
e
r
h
o
w
f
a
s
t
y
o
u
d
o
i
t
,
a
s
l
o
n
g
a
s
t
h
e
f
o
r
c
e
a
n
d
t
h
e
d
i
s
t
a
n
c
e
r
e
m
a
i
n
t
h
e
s
a
m
e
,
t
h
e
w
o
r
k
i
s
t
h
e
s
a
m
e
a
s
w
e
l
l
!
How does it apply to real life?
?
If someone needed to lift a
box to the top of the pile…
There are two ways to do it but the
amount of work is still the same!
They can just pick it up
themselves and lift it; but this
could take lots of effort!
Or, they could use a machine of
some kind that will do the same
work but with less effort!
Machines
A device that helps makes work
easier
by these
3 things:
Changing the size of the force
Changing the direction of the force
The distance over which the force acts
Note: They do not increase the amount of work done or
decrease the amount of work you do
Forces involved:
Input Force
F
e
Force
applied
to
a machine
Output Force
F
r
Force
applied
by
a machine
Two forces, thus two types of work
Work
I
nput
work
d
one
o
n
a
m
achine
a
nd
m
ove
i
t
t
hrough
a
d
istance
=
Input
force
x
the
distance
through
which
that
force
acts
(
input
distance
)
Work
O
utput
Work
d
one
b
y
t
he
m
achine
t
hrough
a
d
istance
=
Output
force
x
the
distance
through
which
the
resistance
moves
(
output
distance
)
Relationship between force and
distance
As 1 increase the other 1 decreases.
Ex. If the force is increased the distance will
decrease.
Inversely Related
Negative trend/negative correlation
Can you get more work out than you put
in?
B
i
g
I
d
e
a
Work output can never be greater
than work input because of friction
How can you increase the work output of a
machine?
Increase the work input or decrease the
friction.
Big Ideas
1) Machines make work easier by these 3 things:
•
Changing the size of the force
•
Changing the direction of the force
•
The distance over which the force acts
2) They do not increase the amount of work done or
decrease the amount of work you do.
Big Ideas
3) The relationship between force and distance is as one
increases the one decreases.
•
Inversely Related
•
Negative trend/negative correlation on graph
4) Work output is never greater than work input because of
friction.
Explore the concept of machines and their role in making work easier by changing force size, direction, and distance. Discover the relationship between force and distance when using machines, and learn about input and output forces involved in work processes. Dive into real-life examples and experiments to grasp the principles of work and power.
Download Presentation
Please find below an Image/Link to download the presentation.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. Download presentation by click this link. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.
E N D
Presentation Transcript
Machines 14-2
Lesson Objectives I can describe what a machine is. I can describe how a machine makes work easier to do. I can describe the relationship between force and distance when using a machine.
Work and Power Lab So last time we saw that the amount of work you do depends on a force being used to move an object a certain distance. The faster you accomplish it, the more power there is! So, if someone has to get themselves up a certain distance, then they have to do the equivalent amount of work It doesn t matter how fast you do it, as long as the force and the distance remain the same, the work is the same as well! The effort Homer needs to jump up is the force! The height of this staircase is the distance The force of the jump x height of the stairs is the work homer accomplished!
They can just pick it up Or, they could use a machine of If someone needed to lift a There are two ways to do it but the themselves and lift it; but this some kind that will do the same How does it apply to real life? box to the top of the pile amount of work is still the same! could take lots of effort! work but with less effort! ? ?
Machines A device that helps makes work easier by these 3 things: Changing the size of the force Changing the direction of the force The distance over which the force acts Note: They do not increase the amount of work done or decrease the amount of work you do
Forces involved: Output Force Fr Force applied by a machine Input Force Fe Force applied to a machine
Two forces, thus two types of work Work Input work done on a machine and move it through a distance =Input force x the distance through which that force acts (input distance) Work Output Work done by the machine through a distance =Output force x the distance through which the resistance moves (output distance)
Relationship between force and distance As 1 increase the other 1 decreases. Ex. If the force is increased the distance will decrease. Inversely Related Negative trend/negative correlation
Can you get more work out than you put in? Big Idea Work output can never be greater than work input because of friction
How can you increase the work output of a machine? Increase the work input or decrease the friction.
Big Ideas 1) Machines make work easier by these 3 things: Changing the size of the force Changing the direction of the force The distance over which the force acts 2) They do not increase the amount of work done or decrease the amount of work you do.
Big Ideas 3) The relationship between force and distance is as one increases the one decreases. Inversely Related Negative trend/negative correlation on graph 4) Work output is never greater than work input because of friction.
