PYQ Vault

Disc about a diameter, a tangent or a parallel axis (parallel and perpendicular axis theorems)

This type of question, asked 8 times: 11 May 2023 S2, 15 May 2023 S2, 10 May 2024 S1, 11 May 2024 S1, 12 May 2024 S1, 16 Apr 2026 S1, 17 Apr 2026 S2, 15 May 2026 S2. All 8 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    11 May 2023 S2

    47
    Moment of inertia of a disc about an axis passing through its centre and perpendicular to its plane is 'I'. The ratio of moment of inertia about a parallel axis tangential to its rim to passing through a point midway between the centre and the rim is

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  2. Question 2

    15 May 2023 S2

    24
    The radius of gyration of a circular disc of radius RR and mass mm rotating about diameter as axis is

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  3. Question 3

    10 May 2024 S1

    8
    If 'I' is moment of inertia of a thin circular disc about an axis passing through the tangent of the disc and in the plane of disc. The moment of inertia of the same disc about an axis perpendicular to the plane and passing through its centre is

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  4. Question 4

    11 May 2024 S1

    13
    Radius of gyration of a thin uniform circular disc about the axis passing through its centre and perpendicular to its plane is KcK_c. Radius of gyration of the same disc about a diameter of the disc is KdK_d. The ratio Kc:KdK_c : K_d is

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  5. Question 5

    12 May 2024 S1

    20
    I1I_{1} is the moment of inertia of a circular disc about an axis passing through its centre and perpendicular to the plane of disc. I2I_{2} is its moment of inertia about an axis AB perpendicular to plane and parallel to axis CM at a distance 2R3\frac{2R}{3} from centre. The ratio of I1I_{1} and I2I_{2} is x9\frac{x}{9}. The value of xx is (R=R = radius of the disc)

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  6. Question 6

    16 Apr 2026 S1

    108
    A Solid sphere has mass M and radius R. Its moment of inertia about a parallel axis passing through a point at a distance R/3 from its centre is

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  7. Question 7

    17 Apr 2026 S2

    105
    Radius of gyration of a thin uniform circular disc about the axis passing through its centre and perpendicular to its plane is KcK_c. Radius of gyration of the same disc about a diamter of the disc is KdK_d. the ratio Kd:KcK_d : K_c is

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  8. Question 8

    15 May 2026 S2

    108
    Moment of inertia of a disc of mass mm and radius RR about the centre of mass and perpendicular to plane is I1I_1 and moment of inertia of disc at a distance 2R3\dfrac{2R}{3} from centre and perpendicular to plane is I2I_2 then I1/I2I_1/I_2 is

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