Summary These notes explain the concept of motion in a straight line in a simple and clear way. It includes definitions of displacement, speed, velocity, acceleration, and all three equations of motion. Graphical explanation of x-t, v-t, and a-t graphs are also c

📘 Chapter: Motion in a Straight Line
(Class 11 Physics – Kinematics Part 1 | NEET/Board)




🌟 1. Introduction
Kinematics is the branch of Physics that deals with the description of motion of objects
without considering the forces causing the motion.

When an object moves along a straight line, it is said to be in rectilinear or one-dimensional
motion.pp




🔸 2. Basic Terms
✅ Distance
Total path length covered by a body

Scalar quantity

Always positive
Unit: meter (m)


✅ Displacement
Shortest distance from initial to final position

Vector quantity (has direction)

Can be positive, negative, or zero
Unit: meter (m)


📝 Example:
If a person walks 10 m east, then 10 m west,

, → Distance = 20 m
→ Displacement = 0 m




🔸 3. Speed & Velocity
✅ Speed
Distance covered per unit time

Scalar




Unit: m/s


✅ Velocity
Displacement per unit time

Vector




🧠 Note:
If object returns to start point → Displacement = 0 → Velocity = 0
But speed ≠ 0




🔸 4. Types of Motion
Type. ​ Description

Uniform motion=​ Equal distances in equal intervals
Non-uniform motion=​ Unequal distances in equal intervals