Answer:
This all simply due to the size of the two water bodies question and the your body size in a bath tub the water is small enough to allow the upthrust displace water out if the tub whereas in a lake the water is bigger and your body size is smaller to allow any noticeable upthrust that would cause an overflow
Assuming that the vectors are acting along the same axis, we
could just simply add or subtract the vectors. Since the F1 is greater than F2,
there would be motion, there would be acceleration, and that the direction of
motion is along the F1.
