Question

A 6.0 kg freshwater fish at the surface of a lake is neutrally buoyant.If the density of its body with its swim bladder deflated is 1060 kg/m3, what volume of gas must be in the swim bladder for the fish to be neutrally buoyant? Express your answer to two significant figures and include the appropriate units.

Answer 1

According to the balance between the buoyant force and the weight of the fish, we require the weight of the gas in the swim bladder plus the weight of the displaced water due to the volume of the fish ( this is the buoyant force acting upward) to be equal to the weight of the fish + plus the weight of the gas in the swim bladder. So, we have
  
  
  
   
   
  
  
   
Now for
   
we have
  
  
   Now putting the given values, we get