alt Hacker NewsBut since potential energy from gravity is mgh and kinetic energy of a projectile is 1/2 mv^2, calculating height and mass of a weight to power the projectile is absolutely straightforward. The terminal velocity of a falling weight has nothing to do with it (even historical trebuchets used a leveraged system in any case).
The point was the leverage can't be simple, like in a traditional trebuchet. Tom ended up with a rope pulling on a cone, with the arm being accelerated over many revolutions before the projectile is let go.
Tom explained it much more straight forward in his video, the blog author tried to be fancy and made it worse.