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: http://zebu.uoregon.edu/1998/ph101/pe1.html
Дата изменения: Wed Oct 14 00:33:33 1998
Дата индексирования: Tue Oct 2 01:37:37 2012
Кодировка:
Поисковые слова: п п п п п п
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Potential Energy
Lesson Plan
Energy Basics:
|
Issac Says: "Let's Learn about Potential
and Kinetic Energy!" |
Potential Energy:
Potential energy exists whenever an object which has
mass has a position within a force field. The most everyday
example of this is the position of objects in the earth's gravitational
field.
Kinetic Energy:
Kinetic Energy exists whenever an object which has
mass is in motion with some velocity .
Everything you see moving about has kinetic energy.
Conservation of Energy
This principle asserts that in a closed system energy is conserved.
This principle will be tested by you, using the experimental apparatus
below. In the case of an object in free fall. When the object is
at rest at some height, h, then
all of its energy is PE.
As the object falls and accelerates due to the earth's gravity , PE is converted
into KE. When the object strikes
the ground, h=0 so that
PE=0, the all of the energy has to
be in the form of KE and the object
is moving it at its maximum velocity. (In this case we are ignoring
air resistance).
Experimental Apparatus
This appartus will drop a mass from different heights. When the
mass strikes the ground, some percentage of its original energy will
be absorbed by the ground.
The parameters you control are:
- The Total Energy (Energy)
- The mass of the object (Mass)
- The percentage of the energy which is absorbed by the surface on
each "bounce" (EAS)
In addition you can measure the height of the object above the surface
by clicking on the black platform upon which the object rests. The
impact velocity of the object will also be given at each bounce.
The functionality of the buttons are as follows:
- Start= Drop the ball after Energy, Mass and EAS have been set;
resume after step or pause has been selected
- Step = Drop the ball once and it rebounds to its maximum height and
then pauses
- Reset = Reset experiment to intial values
- Pause = Pause the animation at any point
Experimental Procedure