How is Misaka's railgun so destructive?

Question

In episode 1 of Railgun, Misaka's railgun up-ends a good chunk of what appears to be an olympic-sized swimming pool. Later in the same episide, it is revealed that her railgun travels at a velocity of 1030 m/s.

However, the numbers don't add up.

Suppose Misaka uses 10 gram coins. At 1030 m/s, that coin has this much energy:

Energy = 1/2 m v^2
       = 1/2 (0.10 kg) (1030 m/s)^2 = 5304.5 kg (m/s)^2
       = 5304.5 Joules

An olympic-sized swimming pool has 2,500,000 kg of water. Based on the image above, that cone probably travels a good 100 meters into the air.

So let's say for benefit of the doubt, that only 10% of the water is lifted 100 meters into the air.

Energy = m g h
       = (0.1 * 2500000 kg) (9.8 m/s^2) (100 m) = 2.45 * 10^8 kg (m/s)^2
       = 2.45 * 10^8 Joules

The coin needs 2.45 * 10^8 Joules of energy to uplift the swimming pool as shown above. But her coin can only provide 5304.5 Joules. There is a difference of about 4 orders of magnitude.

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Okay... Before anyone dismisses this as just another case of Anime physics, let's look at what else could produce so much energy:

1. The spin of the coin is not captured in the net velocity of 1030 m/s. But given the moment of inertia of a little coin, it would need a tremendous (relativistic?) amount of spin to carry 10^8 Joules.
2. The charge of the coin is unspecified in the Anime. Perhaps Misaka somehow polarizes the charge in the coin and somehow makes it release upon contact with the target.
3. The mass-energy (E = mc^2) of the coin is 9 * 10^14 Joules. Is this what she did?

So the question is: Is there any official explanation for where the coin gets so much energy? Or are we left to dismiss this as another case of Anime physics?

Answer 1

While subjective, it was my strong impression from the start that projectile component is indirect (and possibly borderline irrelevant) to her ability.

1. she can produce a lot of energy
2. energy goes where projectile goes
3. however it is not established that projectile carries the energy

Projectile might be just be beacon or focus type of component, possibly purely psychological one (with technique being opposite of just randomly shooting out bursts of uncontrolled electricity).

I remember her shooting large projectile in latter episode, however might still apply.

Answer 2

I argue that it is a case of Anime Physics by refuting the alternative possibilties you suggested.

1. You're right, carrying such an amount of energy as moment of inertia is impossible. Even Misaka's superpowers are a world away from relativistic speeds.
2. The energy cannot be stored as charge in the coin, as it would keep dissipating as "lightning".
3. The energy can't have come from mass energy; besides the lethal radiation that would result, to release mass energy without using antimatter would be to release nuclear energy. Nuclear energy can only be released under extreme pressure (nuclear reactions in bombs are initiated by compressing uranium with the blast of a smaller bomb). If someone could find an example of Misaka finding her coin after she shot it, that clearly refutes the mass energy argument.

Finally, the Myhtbusters proved in this video that a coin travelling at 3 times the speed of sound (around the speed of a bullet) merely dents concrete.