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| | #Energy is transformed from one form to another | | #Energy is transformed from one form to another |
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| − | === Activity 1 - Conservation of mechanical energy in a pendulum === | + | === [[Toer_energy_activity_3|Activity 3 – Energy conversion]] === |
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| − | ==== Objectives of activity: ====
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| − | ==== Pre-requisites ====
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| − | Availability of computer, projector, simulation
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| − | Prior discussion on forms of energy
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| − | ==== Method: ====
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| − | Use the PhET simulation Pendulum Lab.
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| − | For this we will need to open an application called PhET on the
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| − | computer. You can find PhET under Applications> Education>
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| − | Science. PhET is an educational resource that contains computer
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| − | demonstrations of experiments and activities. When we click on Play
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| − | with sims – it will open simulations in various subjects. We will
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| − | click on Physics and scroll down to the simulation on Pendulum Lab.
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| − | When we want to open a simulation, we click on the green
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| − | rectangle which says “Run Now”.
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| − | After running the simulation show the following video
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| − | [[/home/ranjani/Desktop/Conservation of energy/Conservation of Energy in simple pendulum.VOB]]
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| − | ==== Discussion question for activity ====
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| − | '''Questions:'''
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| − | Screenshot #2
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| − | Screenshot #3
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| − | '''Screenshot #4'''
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| − | '''Questions:'''
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| − | ==== Notes (optional) ====
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| − | The motion of a pendulum is a classic example of mechanical energy
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| − | conservation. A pendulum moves it sweeps out a circular arc, moving
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| − | back and forth in a periodic fashion. Neglecting air resistance
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| − | (which would indeed be small for an aerodynamically shaped bob),
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| − | there are only two forces acting upon the pendulum bob. One force is
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| − | gravity. The force of gravity acts in a downward direction and does
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| − | work upon the pendulum bob. However, gravity is an internal force (or
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| − | conservative force) and thus does not serve to change the total
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| − | amount of mechanical energy of the bob. The other force acting upon
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| − | the bob is the force of tension. Tension is an external force and if
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| − | it did do work upon the pendulum bob it would indeed serve to change
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| − | the total mechanical energy of the bob. However, the force of tension
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| − | does not do work since it always acts in a direction perpendicular to
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| − | the motion of the bob. At all points in the trajectory of the
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| − | pendulum bob, the angle between the force of tension and its
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| − | direction of motion is 90 degrees. Thus, the force of tension does
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| − | not do work upon the bob.
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| − | Since there are no external forces doing work, the total
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| − | mechanical energy of the pendulum bob is conserved.
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| | == Concept 3 : Sources of energy == | | == Concept 3 : Sources of energy == |
