After riding his bike for 5 seconds and accelerating at 1.2 m/s?, Bob was riding 8 m/s at the star of his trip. What velocity was Bob riding when he finished his trip?

C).

Explanation:

As we know that capacitance of a given capacitor is

now we know that energy stored in the capacitor plates

here if all the dimensions of the capacitor plate is doubled

then in that case

here area becomes 4 times on doubling the radius and the distance between the plates also doubles

So new capacitance is now

so capacitance is doubled

now the final energy stored between the plates of capacitor is given as

so the final energy is