Question

When a 3.2 kg object is suspended in water, it "masses" 1.5 kg. What is the density of the object?

Answer 1

Weight of object in air   =   m *g   =   3.1g   N   =   d* V * g

   Weight of object in water  =   1.5g   N

   Weight of water displaced   =   (3.2 -1.5)g   =   1.7g   =   d_w* V * g

   Dividing      d /d_w   =   3.2 / 1.7

   but density ofwater   =   10³   kg/m³

   density ofobject   d   =   10³* 3.2 / 1.7   =   1.88 *10³   kg/m³