Physics
posted by Aja .
A nonrotating cylindrical disk of moment of inertia I is dropped onto an identical disk rotating at angular speed w. Assuming no external torques, what is the final common angular speed of the two disks?

You doubled moment of inertia. Angular momentum total must be the same.
If you keep angular momentum the same, then angular speed must be 1/2 the original.
Rotational energy is not conserved. 
1/2w
Respond to this Question
Similar Questions

physics
A 1.6 kg disk with radius 0.63 m is rotating freely at 55 rad/s around an axis perpendicular to its center. A second disk that is not rotating is dropped onto the first disk so that their centers align, and they stick together. The … 
physics
A thin disk, mounted on a frictionless vertical shaft of negligible rotational inertia, is rotating at 495 revolutions per minute. An identical disk (that is not initially rotating) is dropped onto the first disk. The frictional force … 
Physics
Suppose a cylindrical platform with moment of inertia 0.005kg m2 is freely rotating at angular speed 10 rad/s. A disc initially, rotationally at rest with mass 0.6kg and radius 0.1 m is dropped onto the platform so that their centers … 
Physics
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 … 
physics
Two disks are rotating about the same axis. Disk A has a moment of inertia of 3.7 kg · m2 and an angular velocity of +7.3 rad/s. Disk B is rotating with an angular velocity of 9.5 rad/s. The two disks are then linked together without … 
Physics
Two disks are rotating about the same axis. Disk A has a moment of inertia of 3.8 kg · m2 and an angular velocity of +6.7 rad/s. Disk B is rotating with an angular velocity of 8.9 rad/s. The two disks are then linked together without … 
school
Two disks are spinning freely about axes that run through their respective centres (see figure below). The larger disk (R1 = 1.42 m) has a moment of inertia of 1180 kg · m2 and an angular speed of 4.0 rad/s. The smaller disk (R2 = … 
physics
A disk with mass m = 8.1 kg and radius R = 0.33 m begins at rest and accelerates uniformly for t = 18 s, to a final angular speed of ω = 34 rad/s. What is the angular acceleration of the disk? 
Physics
Two disks are rotating about the same axis. Disk A has a moment of inertia of 3.1 kg · m2 and an angular velocity of +8.0 rad/s. Disk B is rotating with an angular velocity of 10.2 rad/s. The two disks are then linked together without … 
physics
Two disks are rotating about the same axis. Disk A has a moment of inertia of 3.6 kg · m2 and an angular velocity of +7.9 rad/s. Disk B is rotating with an angular velocity of 10.6 rad/s. The two disks are then linked together without …