FORMS OF ENERGY

BY: Krystal A. Jack 5B

What is ENERGY???

NON-RENEWABLE

-Oil (petroleum)-Natural gas-coal-uranium (nuclear)

RENEWABLE-solar -wind-geothermal-biomass-hydro-ocean

Sources of ENERGY

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 = F x d 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 ENERGYBigger 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 Caribbeanwind 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)

= m x g x h 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