Kinetic Energy of the Fluid
Reference from the original Physics I textbook.
- Kinetic Energy of the Fluid
The kinetic energy per unit volume of an incompressible fluid is ½ρv², with units J/m³ = Pa. A fluid element of volume V has kinetic energy ½ρVv².
- Related Glossary Terms
- Index
Reviewed physics notes (2)
These corrections keep the original lesson’s purpose while fixing errors in the source edition.
- Bernoulli’s term is energy density, not total energy. — Reference 1
- Use a scalar speed in kinetic energy density. — Reference 1
Glossary and deeper reading · 3 refreshers
These editorial refreshers supplement the reading. Definitions and examples are added guidance; original source wording and recorded answers remain in their original context.
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Kinetic energy
Kinetic energy is energy associated with motion relative to a chosen reference frame. For a nonrelativistic translating object it is one half of its mass times speed squared. For example, doubling a cart’s speed quadruples its translational kinetic energy when its mass stays fixed.
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Fluid
A fluid is a material that flows and continuously deforms under a sustained shear stress. Liquids and gases are both fluids, although their compressibility and other properties can differ greatly. For example, both water in a pipe and air flowing through a duct are fluids.
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Bernoulli’s equation
Bernoulli’s equation relates pressure, fluid speed, and elevation along a streamline in steady ideal flow. Its usual form assumes an incompressible, nonviscous fluid and no added or removed mechanical energy along the path. For example, in a horizontal pipe narrowing under those assumptions, higher flow speed accompanies lower pressure.