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To hold up a certain stationary iron anchor in air takes 200 newtons more than when it is submerged in fresh water. The density of iron is Di=7870 kg/m^3, and by definition, the density of fresh water is Dw=1000 kg/m^3.
Find the weight W, of the anchor in air.
Recall that density of iron is mass per volume, Di= M/V and weight is mass times gravity field, W= M g. Combining these, we write:
(1) W = Di V g which can be seen from Fig. 1 of ...
With explanations and calculations, the problem is solved.