A wheel is rotating freely at angular speed 420 rev/min on a shaft whose rotational inertia is negligible. A second wheel, initi
ally at rest and with 7 times the rotational inertia of the first, is suddenly coupled to the same shaft. (a) What is the angular speed of the resultant combination of the shaft and two wheels
Moment of inertia of second shaft is seven times times the rotational speed of the first i.e. If I is the moment of inertia of first wheel so moment of inertia of second is 7 I
As there is no external torque therefore angular momentum is conserved
B. A hypothesis is just an idea. And can become a Theory if there is some evidence. However a Theory is not a law, but an idea with supportive evidence