Absolutely, useful just to illustrate the scale we're talking about for a given amount of energy stored as a real-world analog easy to recall. Assuming you use

Absolutely, useful just to illustrate the scale we're talking about for a given amount of energy stored as a real-world analog easy to recall. Assuming you used cast iron as weights that has a density of ~7800kg/m³ at regular temperatures, so you're looking at about 10 cubic meters for that 1kWh of potential energy storage using an abundantly available, non-toxic material that will endure.