1. What is Physics?

Physics is the study of matter, energy, space, and time, and how they interact.

At its core, physics tries to answer:

• Why do objects move?

• What is energy?

• How does the universe work?

2. Measurement & Units (Foundation of Everything)

Physics depends on precise measurement.

SI Base Units:

• Length → meter (m)

• Mass → kilogram (kg)

• Time → second (s)

• Temperature → kelvin (K)

• Electric current → ampere (A)

👉 Everything else (velocity, force, energy) is built from these.

3. Kinematics (Motion Without Causes)

Describes how objects move.

Key quantities:

• Displacement (distance with direction)

• Velocity = change in displacement / time

• Acceleration = change in velocity / time

Key equations (constant acceleration):

• v = u + at

• s = ut + ½at²

• v² = u² + 2as

4. Dynamics (Why Objects Move)

Explains motion using forces.

Newton’s Laws:

1. Inertia: Objects resist changes in motion

2. F = ma: Force = mass × acceleration

3. Action–reaction: Every action has an equal and opposite reaction

5. Work, Energy, and Power

Work:

Work = Force × distance
(only when force causes movement)

Energy:

Capacity to do work
Types:

• Kinetic (motion)

• Potential (position)

Law of Conservation of Energy:

Energy cannot be created or destroyed—only transformed.

Power:

Rate of doing work
Power = Work / time

6. Momentum

Momentum = mass × velocity

Key principle:

Conservation of momentum
(total momentum stays constant in a closed system)

7. Waves & Oscillations

Wave types:

• Mechanical (sound)

• Electromagnetic (light)

Important terms:

• Wavelength

• Frequency

• Speed = frequency × wavelength

8. Thermodynamics (Heat & Energy Transfer)

Key ideas:

• Heat flows from hot → cold

• Temperature measures average kinetic energy

Laws:

1. Energy is conserved

2. Entropy (disorder) increases

9. Electricity & Magnetism

Basic quantities:

• Charge

• Current

• Voltage

• Resistance

Ohm’s Law:

V = IR

Magnetism:

Moving charges create magnetic fields.

10. Modern Physics (Advanced but Important)

Includes:

• Quantum mechanics (very small scale)

• Relativity (very fast / massive objects)

Famous ideas:

• E = mc² (mass–energy equivalence)

• Wave–particle duality

🧠 How to Study Physics Effectively

1. Understand concepts first, then formulas

2. Practice solving problems

3. Visualize real-life examples

4. Focus on “why,” not just “how”