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A solid hemisphere is held fully submerged just below the surface of a liquid. Let F1 and F2 be the magnitudes of the hydrostatic forces acting on the curved surface and on the flat (circular) face of the hemisphere respectively. Neglecting atmospheric pressure, find the ratio F1/F2.
- 1/2
- 2/3
- 1/3
- none of these
Correct answer: none of these
Solution
For a hemisphere just submerged near the surface, the resultant on the curved face and that on the flat face are not in a clean fixed simple ratio like 1/2, 2/3, or 1/3 independent of depth and the way 'just pressed below' is interpreted. Standard treatment of this classic problem gives an answer not matching the simple fractions offered, so the correct choice is 'none of these'.
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