Energy

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Energy
Introduction to energy Different types of
energy Kinetic energy Potential
energy Nuclear energy Electric
energy Magnetic energy Heat energy
Presented by Udeshika Madushani udeshika_at_horizonla
nka.org
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Introduction to Energy
Work is done because of a force. As shown in the
figure, the box and car can do work. It implies
the position of an object changes when a force is
applied. So the capacity to perform work is
known as Energy.
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Different types of energy
We can observe different types of work. So
energy also can appear in different
forms. Kinetic energy Potential
energy Nuclear energy Electric
energy Magnetic energy Thermal energy
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Kinetic energy
just click
In motion
Before strike A in motion B stationary
After strike A and B are in motion.
A is in motion, after striking B, B moves. So to
make B move, A has some form of energy. An
object in motion has kinetic energy.
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Think about a turbine in a hydropower station (a
place that generates electricity using water in
motion). Water falls onto a turbine blade, and
the turbine starts to rotate. Why? Because when
water falls onto a turbine blade it has high
energy. When water is in motion it is called the
kinetic energy of water.
Example A table fan Think how kinetic energy
relates in this case. Find more examples of
applications of kinetic energy.
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Potential energy
Fruit on a tree always falls towards earth. Do
you know the reason? Because the earth attracts
all objects. When fruit falls there is work being
done. How can it do work? It must have energy
when it is still on the tree. So, if an object
has energy because of its potential, that form of
energy is called potential energy.
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Example Lets consider a hydropower station as
in our previous example. First we store water in
a reservoir. Stored water, before it falls onto a
turbine, has potential energy. Example We know
a spring can stretch and compress. When it
compresses and stretches it can do work. So there
must be some form of energy. Stretching or
compressing implies use of the springs potential
energy.
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Nuclear energy
The basic element of matter is the atom. Every
material has a well-defined structure. By
changing the structure (the nuclear structure),
of the material we can release a large amount of
energy, which can be used to do work. This energy
is called nuclear energy. In the modern world
nuclear energy has become one of the most
valuable energy sources. We can use nuclear
energy to produce electricity. But we have to use
nuclear energy carefully because it is very
harmful to living things.
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Electric energy Electrons in motion produce what
is called electric energy. Electricity is one of
the most important types of energy because it
powers most modern equipment
No electricity, no light
We use different sources to generate ( to rotate
the turbine) electricity We use different
sources to generate (rotate a turbine)
electricity Potential and kinetic energy of
water Solar energy Kinetic energy of
wind Thermal energy of oil
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Magnetic energy
You might have observed that a magnet can attract
iron or a metal containing iron, like steel. A
magnet also can repel another magnet. A magnet
can project its energy for a limited space. That
space is called a magnetic field. If a piece of
iron can be attracted by a magnet, then the
magnet can do work. So there must be a type of
energy in the magnet. Energy in a magnet is
called magnetic energy. Magnetic energy is used
in electric switches, weight-lifting mechanisms,
etc.
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Heat energy

• Lets consider a hearth (fireplace).
• We burn fuel (coal, oil or charcoal, for
  example) to make fire. We use that fire for
  cooking or heating, which implies fire can do
  work.
• So there must be a type of energy in fire.
• That form is called thermal energy.
• To produce electricity we can use thermal
  energy.
• Thermal energy can transfer from one place to
  another through air.