The reading of a spring balance when a block is suspended from it in air is $60 \,N$. This reading is changed to $40 \,N$ when the block is submerged in water. The specific gravity of the block must be therefore ............
Medium
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(a)
Let $m$ be mass ,
$m = Dv ; D =$ density of mass, $v =$ vol.
$d =$ density of water.
$m \times g = Dv \times g =60$
fully submerged in water
$( D - d ) v \times g =40$
dividing both equations
$\frac{ D - d }{ D }=\frac{2}{3}$
solving this :
$\frac{ D }{ d }=3$
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