Please don't cite ChatGPT as a source or as a caveat, instead show the actual math, which should only be about high school level; kinetic energy formula ½mv² = e,

In perfect conditions assuming no loss through drag, you're looking at the kinetic energy formula which is ½mv² = E (in joules).

E = 1 kWh = 3,600 kilojoules, velocity v at 10 meters is 14 m/s, so we need to calculate m for v = 14 and E = 3600k, which is just under 36735 kg. "about four of those blocks" is "about" correct.

Simpler to use the potential energy formula, surely.

E = mgh

m = E/gh

m = 3.6 * 10^6 J / (9.8 m/s^2 * 10m) = 3.6735 * 10^4 kg