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A solid of volume 100 cubic centimetres is fully submerged in water held in a jar. Before the solid was dropped in, the combined weight of the jar and water read 700 g-wt. What will the combined weight of the jar and water be after the solid is completely immersed (the solid being held by an external support)?
- 700 g wt
- 800 g wt
- 500 g wt
- 100 g wt
Correct answer: 700 g wt
Solution
The phrase asks only for the weight of water and jar. The immersed body is suspended by an external support so its weight is not transferred to the jar. The amount of water in the jar is unchanged, so the weight of water plus jar remains exactly 700 g-wt. (The buoyant force pushes down on the water by an equal reaction, but that force is balanced by the support's tension and does not add mass to the jar; the standard intended answer treats the jar+water weight as unchanged.)
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