Lesson 6 – Centre of Mass & System of Particles

Objective Questions – Set 5
(Matrix Match & Ultimate Traps)

This is the final objective set. Attempt only after mastering previous sets.

Matrix Match Instructions:
Column I contains situations.
Column II contains correct physical conclusions.
Match each entry of Column I with one or more options in Column II.

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Q1. (Matrix Match)

Column I (Situation)

P. System with zero net external force
Q. System observed from non-inertial frame
R. Projectile exploding at highest point
S. Two equal and opposite forces acting on rigid body

Column II (Result)

1. COM moves with constant velocity
2. Pseudo force must be included
3. COM follows original parabolic path
4. Rotation without translation possible

Correct Matching:

P → 1
Q → 2
R → 3
S → 4

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Q2. (Matrix Match)

Column I

P. Isolated system
Q. External force acting
R. Internal explosion
S. Constant external force

Column II

1. Momentum conserved
2. COM accelerates
3. COM velocity unchanged
4. COM motion governed by F = Ma

Correct Matching:

P → 1,3
Q → 2,4
R → 1,3
S → 2,4

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Q3. (Multiple Correct)

Which statements are always true for centre of mass?

A) COM acceleration depends only on external forces
B) COM velocity is same in all frames
C) COM can lie outside the body
D) COM motion simplifies multi-particle analysis

Correct Answers: A, C, D

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Q4. (Integer Type – Logic)

An isolated system initially at rest explodes. One fragment moves with velocity 8 m/s. Find the velocity of centre of mass (m/s).

Answer: 0

Trap: Fragment velocity does NOT decide COM velocity.

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Q5. (Advanced MCQ)

Which conditions guarantee constant velocity of centre of mass?

A) Zero net external force
B) Zero momentum at all times
C) No internal forces
D) Inertial reference frame

Correct Answers: A, D

📘 Centre of Mass & System of Particles – Complete Physics Library

This library is a complete learning package for Intermediate + IIT JEE Physics covering Centre of Mass and System of Particles.

It includes theory, solved examples, objective questions, IIT-level problems, revision strategies, tricks, and exam-oriented guidance.

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📂 Stage 1: Intermediate Complete Notes (Concept Foundation)

1. Part 1
2. Part 2
3. Part 3
4. Part 4
5. Part 5
6. Part 6
7. Part 7
8. Part 8
9. Part 9
10. Part 10

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📂 Stage 2: Advanced Concepts & Applications

11. Part 11
12. Part 12
13. Part 13
14. Part 14
15. Part 15
16. Part 16
17. Part 17
18. Part 18
19. Part 19
20. Part 20

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📂 Stage 3: Objective Questions, Tough Problems & Revision

21. Part 21
22. Part 22
23. Part 23
24. Part 24
25. Part 25
26. Part 26
27. Part 27
28. Part 28
29. Part 29
30. Part 30
31. Part 31
32. Part 32
33. Part 33
34. Part 34
35. Part 35
36. Part 36
37. Part 37
38. Part 38
39. Part 39
40. Part 40
41. Part 41
42. Part 42
43. Part 43
44. Part 44
45. Part 45
46. Part 46
47. Part 47
48. Part 48
49. Part 49
50. Part 50
51. Part 51
52. Part 52
53. Part 53
54. Part 54
55. Part 55
56. Part 56
57. Part 57

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