🧾 Introduction⁷
Motion occurs when an object changes its position with respect to time.
Motion can be described using distance, displacement, speed, velocity, and acceleration.
📌 1. Distance and Displacement
Distance: Total path length (scalar).
Displacement: Shortest straight-line distance between initial and final positions (vector).
🔑 Key Point:
Displacement can be zero even if distance is not zero (when the final position = initial position).
📌 2. Uniform and Non-Uniform Motion
• Uniform Motion: Equal distances covered in equal intervals of time.
• Non-Uniform Motion: Unequal distances covered in equal intervals of time.
📌 3. Speed and Velocity
Speed (v): Distance travelled per unit time.
📌 4. Acceleration
Rate of change of velocity with respect to time.
• Uniform Acceleration: Velocity changes equally in equal intervals.
▪︎ Non-Uniform Acceleration: Velocity changes irregularly.
📌 5. Graphical Representation of Motion
(i) Distance-Time Graph
Straight line → Uniform motion
Curved line → Non-uniform motion
(ii) Velocity-Time Graph
Slope = Acceleration
Area under curve = Distance travelled
📌 6. Equations of Motion (For Uniformly Accelerated Motion)
where:
u = initial velocity
v = final velocity
a = acceleration
t = time
s = displacement
📌 7. Uniform Circular Motion
Motion of an object in a circular path with constant speed.
Example: revolution of Earth around the Sun.
Speed is constant, but velocity changes continuously because direction changes.
📝 Important Questions
1. Differentiate between distance and displacement with examples.
2. Define acceleration and give its SI unit.
3. Derive the three equations of motion using graphical method.
4. Explain why uniform circular motion is an accelerated motion.
