4 ms·
Gravitricity is claiming weights as massive as 5,000 tons and shaft depths from 150m to 1,500m
by gameswithgo 6y ago
Gravitricity is claiming weights as massive as 5,000 tons and shaft depths from 150m to 1,500m
- ben_w 6y agoThat’s equivalent to ~83 tons of lithium ion battery: http://www.wolframalpha.com/input/?i=5000%20tons%20%2A%209.8m%2Fs%2Fs%20%2A%201500m%20%2F%20%280.8MJ%2Fkg%29 http://www.wolframalpha.com/input/?i=5000%20tons%20%2A%209.8...
- twic 6y agoAh - so we can measure the specific capacity of a battery in kilometres of altitude. e = mgh, so h = e/mg. Lead-acid = 0.14 MJ/kg = 14.3 km LiFePO4 = 0.58 MJ/kg = 59.1 km LiNiMnCoO2 = 0.74 MJ/kg = 75.5 km
- ben_w 6y agoYes; how high a fully charged battery could lift itself. I guess it’s similar to counting rocket fuel in seconds (lb_force-seconds per lb_weight).
- tgb 6y agoWhat's the analogous interpretation of the 'seconds' of a rocket fuel? How long you can burn it for?
- cstrahan 6y agoHow long the rocket fuel could offset the force of gravity upon itself, thus suspending itself in-place. In the real world, you'd need the rocket itself (which in turn contains the rocket fuel) which adds weight, and you'd have a difficult time controlling power output so the rocket doesn't drift and lengthen/reduce the burn time -- but that's not the point. The idea is that we want a unit that relates the mass of the fuel with its total energy, and one way to approach that is to consider how long the fuel could offset the force of gravity on that fuel, which gives you a cute unit of measure in terms of time.
- yongjik 6y agoAnd uranium = 80,620,000 MJ/kg = 8,226,530,612 km[1], or about 180% the distance to Neptune. Sometimes I wish we lived in an alternative world with fully developed nuclear power. Think about the possibilities. And no global warming! :/ [1] Not accurate, obviously.