[sopooneo]

Not trying to nit-pick, just trying to confirm my own understanding. But actually, accelerating a mass from 1000km/hr to 2000km/hr should take three times as much energy as from 0km/hr to 1000km/hr, right? I assume the quantity of "four times as much" was just used to get across the notion of energy being proportional to the square of velocity.

[rimantas]

It ment going from 0-1000 to 0-2000, i.e. increasing target speed twice will increase total energy neede four-fold.