Working Energy

• Working energy is the form of energy in which work is done.

a) Kinetic Energy



- Energy of an object that is moving.
- The faster the object moves, the more kinetic eenrgy it possess.
- If two objects move at the same speed, the one with the greater mass has more kinetic enegy.
- A person who runs or cycles possesses kinetic energy.


b) Electrical Energy



- Electric charges moving through electrical conductors such as wires.
- Can be produced by geenrators and power stations.
- Lightnings and lighted bilbs possess electrical energy.


c) Sound Energy



- Produced by vibrating objects.
- Can travel through a medium such as a solid, liquid and gas but it cannot travel through a vacuum because there are no particles in a vacuum.
- Musical instruments produce sound energy.


d) Heat Energy



- Energy found in hot objects.
- Can increases the temperature of an object.
- Flows from a region with a higher temperature to a region with a lower temperature.
- The hotter the object, the higher the heat energy it gives out.
- The sun is the main source of heat energy.


e) Light Energy



- Energy produced and radiated by a luminous object.
- It enables us to see things round us.
- Sun is the main source of light energy.
- A burning candle and firewood produce light energy.


f) Mechanical Energy



- The total kinetic energy and potential energy possessed by an object.
- Produced by machines or by objects changing their positions.
- Mechanical energy is produced by a pendulum that oscillates and a rotating fan blade.

Stored Energy

• Stored energy is the form of energy that is released by chemical or physical reactions.
• The examples of stored energy are:

a) Chemical Energy



- energy stored in substances such as fuels, food, batteries and green plants.
- When these substances undergo chemical reactions, the chemical energy stored inside is released and converted to other forms of energy.
- Food contains chemical energy which is used to provide energy for body.
- Green plants convert light energy from the sun into chemical energy during photosynthesis.

b) Nuclear Energy



- energy stored in the nucleus of an atom.
- Radioactive materials store nuclear energy.
- Released in the form of hear, light, sound and radioactive rays.
- Radioactive rays are dangerous and harmful and also can cause serious illness or even death.

c) Potential Energy



- Energy stored in an object because of its position or its condition.
- Elastic potential energy is the stored energy of stretched or compressed objects.
- A stretched string on a bow and a compressed spring on a spring toy possess potential energy.
- Gravitational potential energy is teh energy possessed by an object due to its position from the ground.
- The higher an object, the more gravitational potential energy it possesses.
- When a crane lifts an object, the object has potential energy.

The various forms and sources of energy

Forms of Energy

1. Energy is the ability to do work.
2. The unit of energy is Joule (J).
3. There are TWO main types of energy, which are: - Working energy and Stored energy