Chapter 19, Problem 16A

a.

To determine

To explain: The way of controlling a density of submarine.

Answer to Problem 16A

Ballast tank controls the density of submarine .

Explanation of Solution

Introduction:

Buoyant force: The force exerted by fluids on the object . It depends upon the density of object as it is directly proportional to the density.

There are ballast tanks in submarines, whichare used to filled water or air and these ballast tanks controlled total density of submarine. When submarine is on the water surface that time ballast tanks are filled with air than total density of submarine will be less than density of surrounding water due to which it can stay on the surface of water on the other hand when submarine is inside the water that time water is filled inside the ballast tanks due to which total density of submarine greater than density of surrounding water due to which submarine can stay inside the water.

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Conclusion:  There are ballast tanks in submarines, whichare used to filled water or air and these ballast tanks controlled total density of submarine.

b.

To determine

To explain: The way of controlling a density of fish.

Answer to Problem 16A

The density of a fish is controlled by contraction and expansion of its air sacs.

Explanation of Solution

Introduction:

Buoyant force: The force exerted by fluids on the object . It depends upon the density of object as it is directly proportional to the density.

Fish have gills by which they inhale oxygen from water and stored it in their body because of oxygen is filled in bladder and it does not effect the weight of fish. The density of a fish is controlled by contraction and expansion of its air sacs.

Conclusion:

The density of a fish is controlled by contraction and expansion of its air sacs means by varying its volume.