clau asked in Science & MathematicsPhysics · 2 years ago

Physics problem! Finding the moment of inertia of a hexagon.?

The six particles (of negligible size) in the figure opposite are connected together by rigid rods of negligible mass. The system forms a perfect hexagon of side 2 m, and the particles have a mass of 1 kg each.

a) Calculate the moment of inertia (no unit needed) of the system about an axis perpendicular to the plane and passing through the centre of mass of the system.

b) Calculate the moment of inertia (no unit needed) of the system about an axis parallel to the one in (a), but passing through one of the masses.

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  • 2 years ago
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    a) If you mark the centre and join each mass to the centre, you see you have 6 equilateral triangles. Distance of each mass to axis (centre) r = 2m.

    Moment of inertia of each mass = mr² = 1 * 2² = 4 kgm²

    Total moment of inertia I = 6 x 4 = 24 kgm²

    b) Total mass M = 6kg

    Axis displaced d=2m. Using parallel axis theorem, moment of inertia through a mass = I + Md² = 24 + 6*2² = 48 kgm²

  • Anonymous
    2 years ago

    it's 60 degrees at 420 .

  • 2 years ago

    Oh sorry, forgot to attach it

    Attachment image
  • Anonymous
    2 years ago

    The hexagon isn't moving because plane, 2D objects don't exist in real life.

    /Thread

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  • 2 years ago

    the figure opposite ?? where is this?

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