Question

A submarine can sink or rise up by filling or emptying its __________.

Answer 1

Archimedes principle

1. A body must adhere to Archimedes' principle in order to float.
2. The Archimedes principle is used to explain the law of flotation or the upward thrust felt when immersed in a fluid.
3. According to Archimedes, the upward buoyant force exerted on a body immersed in a fluid, whether partially or completely submerged, is equal to the weight of the fluid displaced by the body and acts in the upward direction at the center of mass of the displaced fluid.
4. If a body's weight exceeds the weight of the fluid it is dislodging, the body sinks into the liquid.
5. The flotation and sinking of an object are dependent upon the relative density of each other.
6. If the density of an object is greater than the density of water, the object will sink.
7. If the density of an object is less than the density of water, it will float.
8. The submarine can sink or rise in the water by adding and removing air and seawater from the tanks, respectively.
9. The air in a submarine's ballast tanks makes it less dense than the seawater it replaces and allows it to float while it travels on the surface.

Hence, a submarine can sink or rise up by filling or emptying its air.