Ask Question
22 February, 03:11

Two disks are rotating about the same axis. Disk A has a moment of inertia of 3.3 kg · m2 and an angular velocity of + 6.6 rad/s. Disk B is rotating with an angular velocity of - 9.3 rad/s. The two disks are then linked together without the aid of any external torques, so that they rotate as a single unit with an angular velocity of - 2.1 rad/s. The axis of rotation for this unit is the same as that for the separate disks. What is the moment of inertia of disk B?

+5
Answers (1)
  1. 22 February, 05:32
    0
    The angular momentum of a rotation object is the product of its moment of inertia and its angular velocity:

    L = Iω

    L is the angular momentum, I is the moment of inertia, and ω is the angular velocity.

    Apply the conservation of angular momentum. The total angular momentum before disks A and B are joined is:

    L_{before} = (3.3) (6.6) + B (-9.3)

    L_{before} = - 9.3B+21.78

    where B is the moment of inertia of disk B.

    The total angular momentum after the disks are joined is:

    L_{after} = (3.3+B) (-2.1)

    L_{after} = - 2.1B-6.93

    L_{before} = L_{after}

    -9.3B + 21.78 = - 2.1B - 6.93

    B = 4.0kg·m²

    The moment of inertia of disk B is 4.0kg·m²
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “Two disks are rotating about the same axis. Disk A has a moment of inertia of 3.3 kg · m2 and an angular velocity of + 6.6 rad/s. Disk B is ...” in 📙 Physics if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers