Answer:
3. none of these
Explanation:
The rotational kinetic energy of an object is given by:
[tex]K=\frac{1}{2}I \omega^2[/tex]
where
I is the moment of inertia
[tex]\omega[/tex] is the angular speed
In this problem, we have two objects rotating, so the total rotational kinetic energy will be the sum of the rotational energies of each object.
For disk 1:
[tex]K_1 = \frac{1}{2}I (\omega)^2 = \frac{1}{2}I\omega^2[/tex]
For disk 2:
[tex]K_2 = \frac{1}{2}I(-\omega)^2 = \frac{1}{2}I\omega^2[/tex]
so the total energy is
[tex]K=K_1 + K_2 = \frac{1}{2}I\omega^2 + \frac{1}{2}I\omega^2 = I\omega^2[/tex]
So, none of the options is correct.
