Physics

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Two disks are rotating about the same axis. Disk A has a moment of inertia of 4.53 kg·m2 and an angular velocity of +4.55 rad/s. Disk B is rotating with an angular velocity of -6.86 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 -2.24 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?

  • Physics -

    Angular momentum is conserved.
    Ia*wa + Ib*wb = (Ia + Ib)*wfinal
    4.53*4.55 - 6.86*Ib = (4.53+Ib)*2.24

    Solve for Ib.

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