5.0     INTRODUCTION

WORK (W) – Work is done when a force (F) causes an object to move a distance (d) in the direction of the force.

Mathematically, work is given by;

W = F × d cos(θ)

Where;

θ is the angle between the force and the direction of motion,

(Work is measured in joules, J).

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          5.1     ENERGY AND ITS FORMS

Energy is the capacity to do work. It exists in various forms, such as kinetic energy (energy of motion) and potential energy (stored energy).

FORMS OF ENERGY

• Kinetic Energy (KE): This is the energy possessed by an object due to its motion.
• Mathematically,

KE = (1/2)mv²

where m is mass and v is velocity.

• Potential Energy (PE): This is the energy stored in an object due to its position or configuration.
• Mathematically,

PE = mgh

where m is mass, g is the acceleration due to gravity,

  h is height above a reference point.

• Mechanical Energy: This is the sum of kinetic and potential energy in a system. It is conserved in the absence of non-conservative forces (like friction).
• Thermal Energy: This is the energy that comes from the temperature of matter. It is the total kinetic energy of the particles in an object.
• Chemical Energy: This is the energy stored in the bonds of chemical compounds. It is released or absorbed during a chemical reaction.
• Electrical Energy: This is the energy caused by the movement of electrons. It can be converted into other forms of energy, such as light or heat.
• Nuclear Energy: Energy released during nuclear fission or fusion processes, typically used in nuclear power plants.

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POWER (P) – Power is the rate at which work is done or energy is transferred. The formula for power is:

P = W/t

Where W is work done and t is the time taken.

It is measured in watts (W)           ;        1 watt = 1 joule/second.

          5.2     CONSERVATION OF ENERGY

The principle of conservation of energy states that energy cannot be created or destroyed, only transformed from one form to another.

The total energy in a closed system remains constant i.e,

                             KE _initial + PE _initial = KE _final + PE _final

          5.3     ENERGY CONVERSION

Energy conversion is the process of changing energy from one form to another. EXAMPLE OF ENERGY CONVERSION 

• Chemical to Thermal: Burning fossil fuels (like coal or oil) releases thermal energy.
• Mechanical to Electrical: Turbines convert mechanical energy from wind or water into electrical energy.
• Solar to Electrical: Solar panels convert sunlight directly into electrical energy.

5.4     DEVICES USED IN ENERGY PRODUCTION

• Turbines: Convert kinetic energy from wind or water into mechanical energy, which is then converted into electrical energy.
• Generators: Convert mechanical energy into electrical energy using electromagnetic induction.
• Solar Collectors: Devices that capture solar energy and convert it into thermal energy for heating purposes.
• Solar Panels: Convert sunlight directly into electrical energy using photovoltaic cells.

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     5.5     SOURCES OF ENERGY

RENEWABLE ENERGY SOURCES

• Solar Energy: Energy from the sun, harnessed using solar panels and collectors.
• Wind Energy: Energy generated from wind using wind turbines.
• Biomass: Organic materials (like plant and animal waste) used for energy production.

NON-RENEWABLE ENERGY SOURCES

• Coal: A fossil fuel that is burned to produce thermal energy.
• Crude Oil: A liquid fossil fuel used to produce gasoline, diesel, and other petrochemicals.
• Natural Gas: A fossil fuel used for heating, electricity generation, and as a chemical feedstock.