A cubical block of wood weighing 200 g has a lead piece fastened underneath. Find the mass of the lead piece which will just allow the block to float in water. Specific gravity of wood is 0’S and that of lead is 11.3.
The mass of wood, 
Let the mass of the lead be 
Therefore, total mass of the system, 
—————(1)
Density of wood, 
Volume of the wooden block, 
Density of lead, 
Volume of lead piece, 
Therefore, the volume of water displaced would be equal to the total volume.
The buoyant force is given by 
——————(2)
This is equal to the weight of the system. Therefore, equating (1) and (2) we get
Thus, the mass of lead piece is 54.8 g.
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