Angular Velocity & Mass: Shaft Rotation & Disc Effects

[luk4rite]

How does the angular velocity change with increase in the mass?
For example : if there is a shaft rotating at 1500 Rpm , then if a disc of 5 kg is fastened , does the angular velocity of the disc will be same as 1500 RPM , and what happens to the RPM if the disc mass is 50Kg.

 

[Fewmet]

How does the angular velocity change with increase in the mass?
For example : if there is a shaft rotating at 1500 Rpm , then if a disc of 5 kg is fastened , does the angular velocity of the disc will be same as 1500 RPM , and what happens to the RPM if the disc mass is 50Kg.

Momentum (angular or translational) is conserved. If the extra mass were simply attached from rest to the shaft, the mass would go from I$\omega$=0 to some rotational momentum greater that zero. The spinning shaft would have to lose enough angular velocity such that the sum of the rotational momenta (those of the 5 Kg mass and of the shaft) was the same.