Hello peteroznewman,

I was wondering exactly like amir007; I get what you mean with your laptop example, but let's take a structure which is partially immerged in water.

This structure has 3 bodies (A, B and C). 'A' is out of water and is subjected to the gravity only; 'B' and 'C' are subjected to gravity and the Archimede effect ('buoyancy' I think in english ?). How would you consider this Archimede effect if you wish to apply an equivalent acceleration (Aeq = gravity-buoyancy) only on bodies 'B' and 'C' ?

I guess you could just apply a remote force on bodies 'B' and 'C' which represent the buoyant force, but I hope my example enlights why it could be interesting to be able to apply an acceleration on selected bodies. What do you think ?

Thanks for your answer. Regards,