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Chapter 11 of 14
Revision Notes

System of Particles and Rotational Motion

CBSE · Class 11 · Physics

Quick revision notes for System of Particles and Rotational Motion — CBSE Class 11 Physics. Key concepts, formulas, and definitions for last-minute revision.

124 questions88 flashcards5 concepts

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Key Topics to Revise

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1. Rigid Body and Types of Motion

  • A rigid body is a body with a perfectly definite and unchanging shape, and the distances between all pairs of particles do not change.
  • No real body is truly rigid, because real bodies deform under forces, but the deformation is often negligible.
  • A rigid body not fixed in any way is either in pure translation or in a combination of translation and rotation.
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2. Centre of Mass and Centre of Gravity

  • The centre of mass is the mass-weighted mean position of a system of particles.
  • If the origin is chosen at the centre of mass, then Σ mi ri = 0.
  • For two particles of equal mass, the centre of mass lies exactly midway between them.
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3. Motion of Centre of Mass and Linear Momentum

  • Only external forces determine the motion of the centre of mass.
  • Internal forces cancel in pairs by Newton's third law.
  • The centre of mass moves as if all the mass of the system were concentrated there and all external forces acted there.
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4. Vector Product, Torque and Angular Momentum

  • The vector product of two vectors gives a vector perpendicular to the plane of the two vectors.
  • The magnitude of the vector product is ab sinθ.
  • The vector product is not commutative: a × b is not equal to b × a.

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Full Notes

Key Concepts

An ideally rigid body hasThe centre of mass isThe centre of mass moves asThe total momentum of a systemThe vector product of a

Frequently Asked Questions

What are the important topics in System of Particles and Rotational Motion for CBSE Class 11 Physics?
System of Particles and Rotational Motion covers several key topics that are frequently asked in CBSE Class 11 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in System of Particles and Rotational Motion — CBSE Class 11 Physics?
Understand the core concepts first, then work through the 124 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

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