well.....
Archimedes principle has nothing to do with the weight of the body (we all know it)...it means dat archimedes principle is independent of the acceleration due to gravity......it depends only on the volume of the body immersed...
hence it shud hold good in the cases u hav mentioned....
always remember that: B= Vdg (V- vol immersed)
(d-density of liquid)
(g-acceleration due to gravity of dat planet)
watz more intereting is:in the cases u hav said, the volume of the immersed body changes due to the external forces..but archimedes principle is valid..