Transcript forms of energy

FORMS OF ENERGY
BY: Krystal A. Jack 5B
What is ENERGY???
Sources of ENERGY
NONRENEWABLE
-Oil (petroleum)
-Natural gas
-coal
-uranium
(nuclear)
RENEWABLE
-solar
-wind
-geothermal
-biomass
-hydro
-ocean
What is ENERGY??
All of the sources in the slide before,
provide us with energy we need to live our
busy lives.
Therefore, Energy is the ability to do
work. People have learned how to change
energy from one form to another so that
we can do work more easily and live more
comfortably. Energy is neither created nor
destroyed, only converted to another form,
i.e. the total energy present at every stage
in a chain of energy conversions is the
same.
Forms of ENERGY
There are various forms of energy.
Gravitational, elastic chemical,
electrical, magnetic, electromagnetic,
thermal nuclear, kinetic, sound.
These are found in different forms, light
heat sound and motion. Which are placed
in two (2) categories: Kinetic and Potential
Energy.
Definition of the Joule
One joule is equal to the energy used to
accelerate a body with a mass of one
kilogram (1kg) using one Newton (1N) of force
over distance of one meter (1m).
One joule is also equivalent to one watt-second.
F= 1
J
Nm or kgm2s-2
d2
James Prescott Joule (1818-1889)
Energy Equation
W =Fxd
work
= force x
displacement
The above is derived from the following
equation:
W = F x d cos Q
Q=0
and
cos Q=1
NB: work and energy can be used interchangeably.
Energy Transformation
Energy is never ‘lost’, but changes
form. This process is known as an energy
conversion or as transferring energy
Heat can be transferred with:
 Conduction
 Convection
 Radiation
Thermal Energy
Thermal energy is always a
product and by-product of every
transformation.
Example of the conversion of electrical energy to
other forms and vice versa.
Energy Source in the Caribbean
WIND ENERGY
Bigger windmills mean lower cost per kWh.
Therefore the mainstream of the market is
2-3 MW (Mega Watt = 2000-3000 kW peak
capacity) windmills. Their average yield is
up to 1 MW, depending on wind conditions.
Energy Source in the Caribbean
In Western hemispheres this is currently also seen as a
practical limit because of the limitations to place wind
mills on land (people do not like the view). Ten percent,
as useful as it is, is not even covering the growth of
energy use.
For the big windmills the best option to expand is
offshore wind parks.
Energy Source in the Caribbean
• This can significantly increase the wind penetration to
60% or more. While the pure cost per kWh of the wind
energy is lower than the big systems, the average cost of
wind and diesel is better.
•
The smaller systems are easy to install and maintain. For
the Caribbean -and similar markets- this is clearly the
way to go.
Energy Source in the Caribbean
wind turbines in Grenada
Law of conservation of energy
The kinetic energy with which an object
strikes the ground is dissipated as heat,
sound, etc. This is an example of the
principle of conservation of energy.
It can also simply state that energy may
neither be created nor destroyed.
Law of conservation of energy
The most commonly used example is the pendulum:
• The formula to calculate the potential energy is:
• EP = mgh
• The mass of the ball = 10kg
The height, h = 0.2m
The acceleration due to gravity, g = 9.8 m/s^2
Substitute the values into the formula and you get:
• EP = 19.6J (J = Joules, unit of energy)
Kinetic and Potential Energy
Kinetic Energy is
the motion of
waves, electrons,
atoms, molecules,
substances and
objects.
Potential Energy is
the same as
‘stored’ energy,
which is held
within the
gravitational field.
Potential Energy
•
Gravitational Potential Energy is energy that an object
has because of its height above some arbitrarily chosen
reference point (usually the ground). It is stored as a
result of the gravitational pull of the Earth for objects.
•
Elastic Potential Energy is energy stored in stretched or
compressed elastic materials or devices, e.g. a wound-up
clock spring, a drawn arrow, stretched rubber bands.
•
Chemical Potential Energy is energy locked up in
chemical compounds, e.g. in the bonds of gasoline
molecules.
Gravitational Potential Energy
Gravitational potential energy, EP, of an object may be
expressed mathematically as follows:
EP = mass (kg) x acceleration due to gravity (N kg-1) x height (m)
=mxgxh
or
EP = mg h
Gravitational potential energy is the dependent on two variables:
 Mass
 Height above reference position
Kinetic Energy
Kinetic energy is energy of motion. The kinetic energy
of an object is the energy it possesses because of
its motion. The kinetic energy of a point mass m is
given by:
Please follow on next slide thank you
In the slide before with the
diagrams you may see kinetic
energy being displayed as ‘KE’
but don’t be alarmed it is the
same as ‘EK’.
Thanks for viewing my educational Power Point. please have
a wonderful day.
Good-bye