Part a)
As we know that energy stored inside the capacitor is given as

for a given capacitor we know

Now we can use it in above equation to find the energy



PART b)
If two negative charges are hold near to each other and then released
Then due to mutual repulsion they start moving away from each other
Due to mutual repulsion as the two charges moving away the electrostatic potential energy of two charges will convert into kinetic energy of the two charges.
So here as they move apart kinetic energy will increase while potential energy will decrease
Part c)
As we know that capacitance is given as

here we know that




The answer is gravitational:)
Sure.
Can I use your answer to part-'a' ?
If the angular acceleration is actually 32 rev/min², than
after 1.2 min, it has reached the speed of
(32 rev/min²) x (1.2 min) = 38.4 rev/min .
Check:
If the initial speed is zero and the final speed is 38.4 rpm,
then the average speed during the acceleration period is
(1/2) (0 + 38.4) = 19.2 rpm average
At an average speed of 19.2 rpm for 1.2 min,
it covers
(19.2 rev/min) x (1.2 min) = 23.04 revs .
That's pretty close to the "23" in the question, so I think that
everything here is in order.
Answer:
d) all of the above
Explanation:
the speed, velocity, and acceleration all changes to 0 due to no motion.