Ian Stirling wrote:
Ted Edwards wrote:
Gary Coffman wrote:

Actually, in the boat it displaces its *weight*, not mass, but
otherwise correct.

Unless the boat and block are in different gravitational fields, the
result is the same. W=mg.

The boat and the block are in different gravitational fields.
Say the block is moved down 2m from its position in the boat.

Now, fun question.
Is it now slightly heavier, slightly lighter, or the same weight.
My instinct says it is lighter assuming that the block is now below the
waterline.
Now; For a clue as to why I think this is true I would like to pose another
question.
At what distance from the center of the earth, would the block be
'heaviest'?
There has to be a 'simple' answer for this.

Regards.
Ken.