Q. 214.7( 3 Votes )
Find the ratio of the weights, as measured by a spring balance, of a 1 kg block of iron and a 1 kg block of wood. Density of iron = 7800 kg m-3, density of wood = 800 kg m-3 and density of air = 1293 kg m-3.
Given, Density of iron, ,
density of wood,
density of air
The objects can be thought of as fully immersed in air. Therefore, there will be a buoyant force working upwards.
Let mass of iron be and that of wood be . Let there volumes be and respectively.
The weight of iron block becomes, —————(1)
Similarly, weight of wooden block is —————(2)
Taking ratio of (1) and (2)
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