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[[Category:Physics]]
= Introduction =
= Introduction =
environment? These are some questions we will explore here.
environment? These are some questions we will explore here.
= Concept Map =
= Concept Map =
= Work, Energy and Power =
= Work, Energy and Power =
TEST MATERIAL INPUT IN DIET URBAN WORKSHOP BY GURU
We often use the terms work in ordinary
We often use the terms work in ordinary
conversions in this section.
conversions in this section.
Some of the key ideas to be covered in this section are:
# Work has a physical meaning in relation to the force operating and this is linked to the concept of energy. Such work done can be measured in physical terms.
# Work has a physical meaning in relation to the force operating and this is linked to the concept of energy. Such work done can be measured in physical terms.
# What do we mean when we say an object has energy? We are introduced to the idea of kinetic and potential energy.
# What do we mean when we say an object has energy? We are introduced to the idea of kinetic and potential energy.
# Effectivesness of doing work is called power; work, energy and power have units of measure.
# Effectivesness of doing work is called power; work, energy and power have units of measure.<br><br>
== Concept flow ==
== Concept flow ==
energy is needed to do work. We will explore the idea of work done,
energy is needed to do work. We will explore the idea of work done,
energy, power and energy conversions in this section.
energy, power and energy conversions in this section.
Work always involves some opposing forces. What
Work always involves some opposing forces. What
This is true for any type of work.
This is true for any type of work.
Suppose that instead of lifting the box, we push
Suppose that instead of lifting the box, we push
it across a rough floor. In this case, we are not working against
it across a rough floor. In this case, we are not working against
that exists between the moving the box and the floor.
that exists between the moving the box and the floor.
In physical terms, work done is
In physical terms, work done is
directly proportional to both the applied force and the distance
directly proportional to both the applied force and the distance
[[Image:Energy%20for%20KOER_html_m7d349003.png]]Notice
[[Image:Energy%20for%20KOER_html_m7d349003.png]]<br>Notice
that the work done is the same in all the three cases above though
that the work done is the same in all the three cases above though
the force applied is different. Greater the angle of inclination,
the force applied is different. Greater the angle of inclination,
greater is the force needed.
greater is the force needed. Thus W = F x d if the distance travelled d is in
Thus W = F x d if the distance travelled d is in
the same direction as the force. If the direction in which the object
the same direction as the force. If the direction in which the object
is moving is at angle θ then the distance travelled in the direction
is moving is at angle θ then the distance travelled in the direction
[[Image:Energy%20for%20KOER_html_6f7bb14c.gif]]If
[[Image:Energy%20for%20KOER_html_6f7bb14c.gif]]<br>If
the force is acting perpendicular to the direction of the work done,
the force is acting perpendicular to the direction of the work done,
there is no work done. If you are carrying a heavy bag in your hand
there is no work done. If you are carrying a heavy bag in your hand
for the bag.
for the bag.
W
=== Energy, types of energy-Kinetic and potential ===
=== Energy, types of energy-Kinetic and potential ===
[[Image:Energy%20for%20KOER_html_m23570b7e.gif]]'''Understanding
[[Image:Energy%20for%20KOER_html_m23570b7e.gif]]'''<br>
<br>Understanding
Potential Energy'''
Potential Energy'''
==== Activity 1 (Self-evaluation for student) ====
==== Activity 1 (Self-evaluation for student) ====
[[Image:Energy%20for%20KOER_html_m13b54311.gif]]Knowing
[[Image:Energy%20for%20KOER_html_m13b54311.gif]]<br>Knowing
that the PE at the top of the stairs is 50 J, what is the potential
that the PE at the top of the stairs is 50 J, what is the potential
energy at the various positions?
energy at the various positions?
<br>
<br>
=== Potential Energy – Kinetic energy changes during free fall ===
=== Potential Energy – Kinetic energy changes during free fall ===
<br>
<br>
[[Image:Energy%20for%20KOER_html_12d7d970.gif]]
<br>
=== Conservation of energy ===
=== Conservation of energy ===
==== Method: ====
==== Method: ====
[[Image:Energy%20for%20KOER_html_m72c98b84.png]]Use
[[Image:Energy%20for%20KOER_html_m72c98b84.png]]
the PhET simulation Pendulum Lab.
[http://phet.colorado.edu/en/simulation/pendulum-lab Use the PhET simulation Pendulum Lab]
the green rectangle which says “Run Now”.
the green rectangle which says “Run Now”.
==== Running the simulation ====
==== Running the simulation ====
# What do you think will happen to the pendulum next?
# What do you think will happen to the pendulum next?
Screenshot #2
'''Screenshot #2'''
[[Image:Energy%20for%20KOER_html_m4498abd8.png]]'''Questions:'''
[[Image:Energy%20for%20KOER_html_m4498abd8.png]]<br>'''Questions:'''
# What are the values of PE and KE as compared to total energy?
# What are the values of PE and KE as compared to total energy?
Screenshot #3
'''Screenshot #3'''
[[Image:Energy%20for%20KOER_html_706b8b67.png]] '''Questions:'''
[[Image:Energy%20for%20KOER_html_706b8b67.png]]<br> '''Questions:'''
# Look at the graph – what are the variables in the bar chart? Where has the thermal energy come from?
# Look at the graph – what are the variables in the bar chart? Where has the thermal energy come from?
# What do you expect will happen to the simple pendulum?
# What do you expect will happen to the simple pendulum?
==== Mechanics of the simple pendulum ====
==== Mechanics of the simple pendulum ====
total mechanical energy of the pendulum bob is conserved.
total mechanical energy of the pendulum bob is conserved.
=== Power, energy units and conversions ===
=== Power, energy units and conversions ===
and also to describe the energy content of food stuff.
and also to describe the energy content of food stuff.
= Energy in the world =
= Energy in the world =
=== Small-scale storage ===
=== Small-scale storage ===
[[Image:Energy%20for%20KOER_html_m7a21910d.jpg]][[Image:Energy%20for%20KOER_html_bb112d6.png]]For
[[Image:Energy%20for%20KOER_html_m7a21910d.jpg]][[Image:Energy%20for%20KOER_html_bb112d6.png]]
<br>
<br>
<br>For
small-scale storage of electricity, batteries and fuel cells offer
small-scale storage of electricity, batteries and fuel cells offer
the best course. An electric battery consists of one or more electric
the best course. An electric battery consists of one or more electric
this battery to A. C. at higher voltage and frequency.
this battery to A. C. at higher voltage and frequency.
=== Large scale storage ===
=== Large scale storage ===
= Energy and the future =
= Energy and the future =
The worldwide demand for energy is increasing day
The worldwide demand for energy is increasing day by day. The increasing use of modern means of transport-cars, buses,trains, aero planes , ships, etc., the rapid rise in the overall industrialization; the tremendous growth in population, particularly in the last 40 years, are some of the factors that have led to a tremendous spurt in mankind’s energy requirements. The biggest challenge/problem the world faces today is perhaps 'climate change' or 'global warming' which will lead to mass extinction of all life on earth. One of the major contributors to this is large use of fossil fuels (coal, petroleum) and moving to renewable energy sources is important. Read [http://www.nationofchange.org/2015/06/12/ditching-fossil-fuels-and-switching-to-100-renewables-no-problem-says-stanford-study article on how we can switch to alternative / renewable energy resources]
by day. The increasing use of modern means of transport-cars, buses,
trains, aero planes , ships, etc., the rapid rise in the overall
industrialization; the tremendous growth in population, particularly
in the last 40 years, are some of the factors that have led to a
tremendous spurt in mankind’s energy requirements.
energy produced.
energy produced.
= Evaluation: =
= Evaluation: =
# List some steps to minimize energy wastage
# List some steps to minimize energy wastage
= Teachers' Contributions =
= Additional web resources =
= Additional web resources =
Conservation of Energy, Thermodynamics, Biomass, Fossil Fuel,
Conservation of Energy, Thermodynamics, Biomass, Fossil Fuel,
Combined Cycle Power Generation</u>
Combined Cycle Power Generation</u>
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