The Apple, Hand and the Earth

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The Apple, Hand and the Earth

• Created for CVCA Physics
• By
• Dick Heckathorn
• 20 October 2K 4

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2.
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w is exerted by earth on apple.
w
Fe on apple
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n is exerted by hand on apple.
Fhand on apple
n
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How is Fh on a related to Fe on a?
Fhand on apple
(equal)
(same magnitude)
Are not equal as they are in opposite directions.
Fe on apple
3b.
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What is the net force on the apple?
Fhand on apple
(zero)
(nonzero)
Why?
The apple is not moving.
Fe on apple
3d.
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are they an action-reaction pair?
Since Fh on a and Fe on a are equal opposite,
(they are)
Fhand on apple
(they are not)
Note that both forces are acting on the same
object.
Fe on apple
3d.
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The reason isthey act on
Fhand on apple
the same object
different objects
Thus we can say
Fe on apple
3d.
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If the action force is the earth pulling on the
apple then
Fa on earth
the reaction force is the
apple pulling on the earth.
Fearth on a
3d.
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Thus we can see that Fh on a and Fe on a are
Fhand on a
equal and opposite and
Fa on earth
do not
do
comprise an action-reaction pair.
Fearth on a
3f.
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Another pair of forces are
Fhand on apple
This force pair
does
does not
comprise and action-reaction pair.
Fapple on hand
3g.
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Nellie now pushes upward with her hand on the
apple with 2-N of additional force.
What does the apple do?
still at rest
accelerates up
New
Fhand on a
Why?
There is a net force up on the apple of 2-N
Fa on hand
3h.
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Once the apple leaves the hand
The force of the hand on the apple is
Fh on a
the net force on the apple is
Thus the apple
begins to slows down.
Fe on apple
3d.
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Thats all folks!