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SubjectFree lesson

Introduction to Physics

ClassNotes Team 5 MIN READUPDATED 2 JUL 2026

Physics SSS1 First Term

WEEK 1

Introduction to Physics

Performance Objectives

Students should be able to:

  1. Define Physics
  2. State the Application of Physics
  3. Explain the Fundamental and Derived quantities with their units

Content

Introduction to Physics

Physics falls under a broader category of Science. Science is divided into three areas namely Biology, Physics and Chemistry. The main objective of these subjects is to study and try to understand the universe and everything in it.

What is physics?

Physics is the branch of science which deals with matter and its relation to energy. It involves the study of physical and natural phenomena around us. Examples of these phenomena are the formation of rainbow, occurrence eclipse, the fall of things from up to down, the cause of sunset and sunrise, the formation of shadow and many more.

Physics as a subject is divided into six broad branches as discussed below.

  1.  Mechanics
    This branch deals majorly with motions under the influence of forces. Under this branch, we look into details the aspects of linear, circular and oscillatory motions as well as motion of fluids
  2. Geometrical Optics: This branch takes a keen look at the behaviour of light in various media.
  3. Electricity and magnetism
    This branch looks at the interaction between electric fields and magnetic fields and the applications of such interactions.
  4. Thermodynamics
    This branch looks at how heat as a form of energy is transformed to/from other forms of energy.
  5. Atomic Physics
    This area of study is targeted at the behaviour of particles of the nucleus and the accompanying energy changes.
  6. Waves
    It deals with the study of the propagation of energy through space.

Relationship between physics and other subjects
Physics does not only relate the remaining two science subjects but also enjoys a relationship with other subjects as well.

  1. Physics And Mathematics: Physics relates strongly with mathematics, Many physics concepts are expressed mathematically. Many physics formulae are expressed mathematically.
  2. Physics And Biology Knowledge of lenses in physics is used in making microscope used in the study of cells in biology. Physics formulae are used in the calculation of magnification by microscopes. The knowledge of levers helps to explain locomotion in Biology.
  3. Physics and Chemistry. Physics has helped in explaining forces within atoms and therefore atomic structure. It is this structure of the atom that then determines the reactivity of the atom as explained in chemistry.
  4. Physics and Religion: Orderliness of systems in the universe can be traced back to the Creator. Many wonders of creation include the anomalous expansion of water, the rainbow.
  5. Physics and Geography: Accurate use of instruments and physics concepts can establish weather patterns and explain the formation of rainfall, pressure variations. Use of magnetic properties of lodestone and other materials help navigators to determine direction.
  6. Physics and Technology.

Some areas of technology that requires knowledge of physics are in:
 

a. Medicine.
X-rays, lasers, scanners which are applications of physics are used in the diagnosis and treatment of diseases.

b. communication

Satellite communication, internet, fibre optics are applications of the internet which requires a strong foundation in physics.

c. Industrial applications

In the area of defence, physics has many applications e.g. warplanes, laser-guided bombs which have high-level accuracy.

In the entertainment industry, knowledge of physics has used in mixing various colours to bring out the desirable stage effects

Some Career opportunities in Physics

  • Building Economics
  • Construction Management
  • Medicine and Surgery
  • Dental Surgery
  • Pharmacy
  • Nursing
  • Production Engineering
  • Chemical and Processing Engineering
  • Civil Production Engineering
  • Chemical and Processing Engineering
  • Civil Engineering
  • Electrical and Electronics Engineering
  • Mechanical Engineering

Some courses offered at the colleges and universities that require the knowledge of physics.

At University level, some of the courses are offered.

  1. Bachelor of Architecture.
  2. Bachelor of pharmacy.
  3. Bachelor of medicine.
  4. Bachelor of dental surgery.
  5. Bachelor of Science (nursing)
  6. Bachelor of education science (physics)
  7. Bachelor of Science (Electrical and Electronic Engineering)
  8. Bachelor of Veterinary Medicine.

At College level, some of the courses are offered.

  1. Diploma in building and construction.
  2. Diploma in Mechanical Engineering.
  3. Diploma in physiotherapy.
  4. Diploma in Electrical Engineering.
  5. Diploma in computer science.

Fundamental Quantities

Are the basic quantities that are independent of others and cannot be defined in terms of the other quantities or derived from them, while most quantities depend on them.

The three most important basic and fundamental quantities are length, time and mass.

Length may be defined as the extent of space or distance extended.

Mass is defined as the quantity of matter or material substance.

Time is defined as that in which events are distinct with respect to before or after.

Fundamental Units are the basic units upon which other units depend. They are actually the units of the fundamental quantities.

The table below shows fundamental quantities and units

Quantities

Units

Unit Abbreviations

Length

Metre

M

Time

Second

S

Mass

Kilogram

Kg

Electric current

Ampere

A

Temperature

Kelvin

K

Amount of substance

Mole

Mol

Note that units in the above table are SI (Systeme International) units, it is the most important system today and it is used in scientific work today.

Derived quantities and units are those gotten by some simple combination of the fundamental quantities and units, hence it is so, they are dependent on the fundamental quantities and units, the derivations of the quantities units are tabulated below

Derived quantities

Derivation

Derived units

Area (A)

Length x breath

m2

Volume (V)

Length x breadth x height

m3

Density

Mass/volume

Kg.m-3

Velocity (v)

Displacement/time

m.s-1

Acceleration (a)

Change in velocity/time

m.s-2

Force (F)

Mass x acceleration

Newton, N

Energy or Work (W)

Force x distance

Joule (Nm)

Power (P)

Work/time

j.s-1 (or watt, W)

Momentum

Mass x velocity

Kg.m.s-1;Ns

Pressure (P)

Force/area

N.m-2,( Pascal, Pa) Per second or s-1

Frequency (f)

Number of oscillations/time

(hertz, Hz)

Electric charge

  

C (coulomb)

Electric Potential Difference

  

V (volt)

Electric resistance

  

Ohm

Electric capacitance

  

Farad (F)