[ynniv]

... by something lowered on a tether. If you think that's comparable to touching a rotor, you don't know much about rotors. mv^2!

[hnriot]

touching a rotor chops your hand off. Getting hit in the head by delivery of dog food kills you. It's kinetic vs potential energy. for your kinetic energy equation you need a lot of speed and a lot of mass. You can have one of those, but not both.