Class 9 Physics: Unit 2
Kinematics - Comprehensive Study Guide
1. Introduction to Kinematics
Introduction: Physics ki wo branch jo sirf motion ko describe karti hai bina un forces ka zikar kiye jo motion paida karti hain, usay Kinematics kehte hain.
Definition: "The study of motion of an object without discussing the cause of motion is called kinematics."
2. Rest and Motion
Rest: Agar koi body apne surroundings ke lehaz se apni jagah change na kare.
Motion: Agar koi body apne surroundings ke lehaz se apni jagah change kare.
Example: Ek chalti hui car mein betha musafir car ke lehaz se rest mein hai lekin bahar khade shakhs ke liye motion mein hai.
3. Scalars and Vectors
| Type | Definition | Examples |
|---|---|---|
| Scalars | Jinhein describe karne ke liye sirf magnitude chahiye ho. | Mass, Time, Speed |
| Vectors | Jinhein magnitude aur direction dono chahiye hon. | Velocity, Displacement, Force |
4. Terms Associated with Motion
Distance (S): Total length of path covered. (Scalar)
Displacement (d): Shortest distance with direction. (Vector)
Speed (v): Distance covered in unit time. (v = S/t)
Velocity (v): Rate of displacement. (v = d/t)
Acceleration (a): Rate of change of velocity. [a = (vf - vi) / t]
5. Equations of Motion
2. S = vit + ½ at2
3. 2aS = vf2 - vi2
🧠Quick Revision Quiz (10 MCQs)
1. A change in position is called:
(A) Speed (B) Velocity (C) Displacement (D) Distance
▶ See Answer
(C) Displacement
2. Which is a vector quantity?
(A) Speed (B) Distance (C) Displacement (D) Power
▶ See Answer
(C) Displacement
3. The SI unit of acceleration is:
(A) ms⁻¹ (B) ms⁻² (C) kmh⁻¹ (D) ms
▶ See Answer
(B) ms⁻²
4. Speed of 36 kmh⁻¹ in ms⁻¹ is:
(A) 10 (B) 20 (C) 25 (D) 30
▶ See Answer
(A) 10 ms⁻¹
5. Slope of distance-time graph is:
(A) Acceleration (B) Speed (C) Force (D) Weight
▶ See Answer
(B) Speed
6. Gravitational acceleration 'g' is:
(A) 10 ms⁻² (B) 5 ms⁻² (C) 20 ms⁻² (D) Zero
▶ See Answer
(A) 10 ms⁻²
7. Number of equations of motion:
(A) 1 (B) 2 (C) 3 (D) 4
▶ See Answer
(C) 3
8. Velocity at highest point when thrown upward:
(A) Max (B) 10 (C) Zero (D) -10
▶ See Answer
(C) Zero
9. Vector representation:
(A) Light (B) Bold letters (C) Numbers (D) Italics
▶ See Answer
(B) Bold letters
10. Pendulum motion type:
(A) Linear (B) Vibratory (C) Random (D) Rotatory
▶ See Answer
(B) Vibratory Motion
UNIT 2 COMPLETE ✅
Aapka Unit 2 ab har lehaz se mukammal hai. Study jari rakhein!