Ch 9Mechanical Properties of Fluids — Class 11 Physics, concept-first.

SUB TOPIC 1 of WBCHSE's Unit 7 ("Properties of Bulk Matter") ended with a single, sharp observation: a fluid -- a liquid or a gas -- has a shear modulus of rigidity of exactly zero.

When a fluid flows, the individual particles making up the fluid can move past one another in one of two fundamentally different ways, and telling these two ways apart is the first step in understandi…

Viscosity is the property of a fluid by which it offers internal resistance -- essentially, a kind of internal friction -- to the relative motion between its own adjacent layers.

Stokes' law. When a small solid sphere moves at a constant, sufficiently slow speed through a viscous fluid that is otherwise at rest (or, equivalently, when a viscous fluid flows steadily past a stat…

Whether a given flow turns out to be streamline or turbulent depends, as seen in Section 9.2, on the flow speed -- but it also depends on the fluid's density and viscosity, and on the size of the tube…

Bernoulli's theorem is, at its heart, simply the principle of conservation of energy applied to a moving, ideal fluid.

Bernoulli's theorem, together with the equation of continuity (which follows from conservation of mass for an incompressible fluid, and states that for any two cross-sections of a pipe of varying area…

A molecule deep inside the bulk of a liquid is surrounded, in every direction, by other liquid molecules within the short range over which intermolecular attractive forces act (this range is called th…

When a liquid surface meets a solid surface -- for instance, where the curved surface of water inside a glass tube meets the tube's inner glass wall -- the liquid surface meets the solid at a definite…

Because a liquid's free surface behaves like a stretched elastic membrane, always trying to contract to the smallest possible area, a curved liquid surface always has a slightly higher pressure on its…

Capillarity is the name given to the rise (or, in some cases, the fall) of a liquid inside a sufficiently narrow tube, called a capillary tube, when the tube is dipped vertically into a wide, open res…

This chapter developed the mechanics of fluids -- both their motion and their surface behaviour -- along exactly the topics WBCHSE's Unit 7 SUB TOPIC 2 lists:

Sample papers and previous-year board questions for this subject.