Conservation of Momentum Roed and Alyssa

7/29/2019 Conservation of Momentum Roed and Alyssa

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By:

Roed S. Culata

Alyssa Marie A. Ton-ogan


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When Momentum, or anyquantity in Physics, does notchange, we say it is .


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is inertia inmotion.


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The idea that Momentum is

conserved when no external forceacts is elevated to a central law of

mechanics is called the.


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Law of Conservation of

Momentum states:

.


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Consider a collision between twoobjects - object 1 and object 2. Forsuch a collision, the forces acting

between the two objects are equalin magnitude and opposite in

direction (Newton's third law).


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This statement can be expressed in

equation form as follows.

F1 = -F2(the Forces are equal in magnitude, opposite in

direction)


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The forces act between the two

objects for a given amount of time.Regardless of how long the time is,it can be said that the time that the

force acts upon object 1 is equal tothe time that the force acts upon

object 2.


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Therefore,

t1 = t2


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Since the forces between the two objectsare equal in magnitude and opposite indirection, and since the times for which

these forces act are equal in magnitude, itfollows that the impulses experienced by

the two objects are also equal inmagnitude and opposite in direction.


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Therefore,

F1*t = -F2*t(The impulse are equal in magnitude, opposite indirection)


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But the impulse experienced by an object is

equal to the change in momentum of thatobject (the impulse-momentum change

theorem). Thus, since each object

experiences equal and oppositeimpulses, it follows logically that they

must also experience equal and

opposite momentum changes.


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Therefore,

m1*v1 = -m2*v2(The momentum changes are equal in

magnitude, opposite in direction)


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The basic example:


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Example 1:A cannon is being fired.
http://www.gifbin.com/982696


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Action:

The force on the cannonball

inside the cannon barrel is equaland opposite to the force causing

the cannon to recoil.


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Explanation:

The momentum before firing is zero.After firing, the net momentum is

still zero, because the momentum ofthe cannon is equal and opposite to

the momentum of the cannonball.


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Example 2:

A cue ballhits an 8 ball

head-on.


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a) An external force acts onthe 8-ball system, and its

momentum increases.


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b) An external force acts onthe cue-ball system, and itsmomentum decreases.


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c) No external force acts on the

cue ball + 8-ball system, andmomentum is conserved

(simply transferred from onepart of the system to the other).


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The End

Conservation of Momentum Roed and Alyssa

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