Buoyancy

In physics, buoyancy is an upward force on an object immersed in a fluid (i.e. a liquid or a gas), enabling it to float or at least to appear to become lighter. If the buoyancy exceeds the weight, then the object floats; if the weight exceeds the buoyancy, the object sinks. If the buoyancy equals the weight, the body has neutral buoyancy and may remain at its level. If its compressibility is less than that of the surrounding fluid, it is in stable equilibrium and will, indeed, remain at rest, but if its compressibility is greater, its equilibrium is unstable, and it will rise and expand on the slightest upward perturbation, but fall and compress on the slightest downward perturbation. It was the ancient Greek, Archimedes of Syracuse, who first discovered the law of buoyancy, sometimes called Archimedes' principle:

Related Topics:
Physics - Force - Fluid - Liquid - Gas - Weight - Compressibility - Unstable - Archimedes - Syracuse

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:The buoyant force is equal to the weight of the displaced fluid.

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Typically, the weight of the displaced fluid is directly proportional to the volume of the displaced fluid (Specifically if the surrounding fluid is of uniform density.) Thus, objects with greater volume have greater buoyancy.

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Suppose a rock's weight is measured at 10 newtons when suspended by a string in a vacuum. Suppose that when the rock is lowered by the string into water, it displaces water whose weight is 3 newtons. The force it then exerts on the string from which it hangs will be 10 newtons minus the 3 newtons of buoyant force: 10 − 3 = 7 newtons.

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Buoyancy is the underlying principle of many vehicles such as boats, ships, balloons, and airships.

Related Topics:
Vehicle - Boat - Ship - Balloon - Airship

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