Not trying to nit-pick, just trying to confirm my own understanding. But actually, accelerating a mass from 1000km&#x2F;hr to 2000km&#x2F;hr should take <i>three</i> times as much energy as from 0km&#x2F;hr to 1000km&#x2F;hr, right? I assume the quantity of &quot;four times as much&quot; was just used to get across the notion of energy being proportional to the square of velocity.