Answer:
(a) Angular speed of resultant combination will be rev/min
(b) Fraction of total energy loss will be 0.9
Step-by-step explanation:
We have given angular speed of the first wheel

According to question moment of inertia of second wheel is 9 times the moment of inertia of first wheel
So

(a) Now according to law of conservation of angular momentum



(b) Change in rotational kinetic energy will be equal to
.......eqn1


Putting these values in eqn 1
Change in kinetic energy will be 0.9