Question

Is this correct??
Metal block weighs 500g in air and 446g completely submerged in water.

Calculate density and relative density.

Density of water = 1000kg/m3

BF (Buoyant force) will be 500g-446g = 0.54 g (or 0.054 kg).

For volume: If BF = Density(water)*V*g

then V = BF/density*g = 0.054/1000*9.81
=5.50*10^-6 m3

Density metal = m/V = 0.50Kg/5.50*10^-6 m3
=90909.10 Kg/m3


Relative density = 90909.10/1000
=90.91

Is this correct???

Answer 1

500 - 446 = 54 g = mass (not weight or force) of water displaced which is 54 cubic centimeters
so
density of block = 500 g/54 cm^3
= 9.26 g/cm^3
= 9260 kg/m^3

9260/1000 = 9.260 = relative density

Answer 2

by the way the relative density of steel is about 8

Answer 3

When the unit is gm you can take it as mass.(To mention weight unit is 'gm-weight'.)
volume of water displaced = volume of block= 54 cc ( mass/density of water displaced = 54gm/1gm per cc)
Thus density of block = mass of block in air / volume of block = 500/54 = 9.26 g/cc

Answer 4

it is correct