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NEET Physics · Rotational Motion

Centre of mass

Taught in NCERT Class 11 Physics, Chapter 6: System of Particles and Rotational Motion.

2 verified questions: Easy 0 · Medium 2 · NEET level 0

Sample questions

Sample 1Medium

In an x-y plane three point masses are drawn: 1 kg at the origin (0, 0), 2 kg at (3 m, 0) and 3 kg at (0, 3 m). Where is the centre of mass of the system?

  1. A

    (1.5 m, 1 m)

  2. B

    (1 m, 1 m)

  3. C

    (2 m, 1.5 m)

  4. D

    (1 m, 1.5 m)

Show the answer
The answer is D.

X = (1×0 + 2×3 + 3×0)/6 = 1 m and Y = (1×0 + 2×0 + 3×3)/6 = 1.5 m.

  • A.

    This swaps the x and y coordinates.

  • B.

    (1 m, 1 m) is the centroid of the triangle, which applies only for equal masses.

  • C.

    (2 m, 1.5 m) divides the x-moment by 3 instead of the total mass 6 kg.

NCERT: Class 11 Physics, Chapter 6

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