So it's likely that is enough force to initiate the chain reaction? Any guess to the explosion's efficiency since there is no tamper? I know Little Boy didn't even achieve 2% but still yielded 14KT.
It's a good thing it's so difficult to isolate U-235!
Critical mass is over 50kg so let's say I have 2 halves of a sphere of the isotope U-235, each weighing 30 kg. I drop one onto the other so that they form a supercritical sphere. No doubt a chain reaction would begin, but I assume it would produce energy on the level of a nuclear reactor rather...