Transcript Work and Machines - Monroe County Schools

Work and Machines
Work equals Force times
Energy
B. Velocity
C. Distance
D. Mass
A.
100%
0%
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0%
B.
0%
C.
D.
Work is measured in
Meters
B. Pounds
C. Joules
D. Newtons
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Work and
Machines
1.
2.
Describe what a machine is and
how it makes work easier to do.
Relate the work input to a machine
to the work output of the machine.
Which of these is an example of
work being done on an object?
A.
B.
C.
D.
Holding a heavy piece of
wood at a construction site.
Trying to push a car that
doesn’t move out of deep
snow.
Pushing a child on a swing.
Holding a door shut on a
windy day so it doesn’t blow
open.
86%
9%
5%
0%
A.
B.
C.
D.
Machines Do Work


1.
2.
3.
A Machine is a device that changes
force.
Machines make work easier to do
in three ways.
Change the size of a force needed.
Direction of a force
Distance over which a force acts.
What do machines do?
A.
B.
C.
D.
Change the amount of
force you exert or the
distance over which you
exert the force.
Increase the amount of
work that is done.
Decrease the amount of
work that is done.
Eliminate friction.
55%
30%
15%
0%
A.
B.
C.
D.
Increasing Force
 The
upward force exerted by the
jack is greater than the downward
force you exert of the handle.
Increasing Distance
 They
will do the same amount of work.
Doing the work over a longer distance
allows them to use less force.
Changing Direction
 When
you use an
ax to split wood,
you exert a
downward force as
you swing the ax
then it changes
into a horizontal
force that splits
the wood apart.
How can a hockey stick be
considered a machine?
A.
B.
C.
D.
It multiplies force.
It multiplies
distance.
It changes
direction.
It reduces friction.
45%
36%
18%
0%
A.
B.
C.
D.
Pulling down on a rope to hoist a
sail on a sailboat is an example of
a machine.
A.
B.
C.
D.
Multiplying the force you
exert.
Multiplying the distance
over which a force is
exerted.
Changing the direction in
which a force is exerted.
Reducing friction.
55%
25%
10%
A.
B.
10%
C.
D.
Input Force
The
force that you apply to
the machine.
It is also known as the Effort
Force.
Output Force
The
force that is applied by
the machine.
It is also known as the
Resistance Force.
A term that means the same thing
as output force is
A.
B.
C.
D.
Input force
Resistance force
Effort force
Multiplying force
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