Motion – Complete Physics Notes (Class 9–10 | NEET/JEE Foundation)

🏃 Motion – Complete Physics Notes

Class 9–10 + NEET/JEE Foundation | Easy English | Full Chapter Covered

🧠 Why Study Motion?

Base of entire Physics (Kinematics → Laws of Motion)
Board exams + competitive exams favourite
Numericals + graphs = scoring area

Human Respiratory System Fully Labelled Colourful Diagram for NEET

Fully labelled colourful respiratory system diagram (NEET)

📌 What is Motion?

An object is said to be in motion if its position changes with respect to time and a reference point.

Key Line: Motion is relative – depends on the observer/reference frame.

📏 Distance & Displacement

Distance	Displacement
Total path length	Shortest straight-line change in position
Scalar quantity	Vector quantity (has direction)
Always positive	Can be zero or positive/negative

Trap: Distance ≥ Displacement (always).

⏱️ Speed & Velocity

Speed	Velocity
Distance / Time	Displacement / Time
Scalar	Vector (direction matters)

Speed = Distance ÷ Time

Velocity = Displacement ÷ Time

NEET/Boards: Average speed ≠ Average velocity (in general).

⚡ Acceleration

Rate of change of velocity with time.

Acceleration (a) = (v − u) ÷ t

Positive acceleration → speeding up
Negative acceleration (retardation) → slowing down

Trap: Zero acceleration does not always mean zero velocity (constant velocity case).

📐 Equations of Uniformly Accelerated Motion

1) v = u + at

2) s = ut + ½at²

3) v² = u² + 2as

Tip: Write known values → choose correct equation.

📈 Graphical Representation of Motion

Distance–Time Graph

Straight line with constant slope → uniform speed
Horizontal line → object at rest
Curved line → non-uniform motion

Velocity–Time Graph

Slope of v–t graph = Acceleration
Area under v–t graph = Displacement

Favourite Q: Area under v–t graph gives displacement.

🔁 Types of Motion

Rectilinear: Straight line motion
Circular: Motion along a circle (speed constant, velocity changes)
Periodic: Repeats after equal time (pendulum)
Uniform: Constant speed
Non-uniform: Changing speed

Trap: In circular motion, speed can be constant but velocity is changing (direction changes).

🧮 Sample Numerical (Quick)

A car starts from rest and attains 20 m/s in 10 s. Find acceleration.

Given: u = 0, v = 20 m/s, t = 10 s → a = (v − u)/t = 2 m/s²

One-Page Memory: Distance ≥ Displacement Slope (v–t) = a Area (v–t) = s v = u + at Circular → v changes

🎯 Exam Strategy

Draw neat graphs with labels
Write units (m, s, m/s, m/s²)
Practice 10 numericals daily
Revise formulas before tests