Comprehensive notes for Chapter 5 Solids and Fluid Dynamics. Covers Properties of Solids, Stress & Strain, Fluid Flow, Bernoulli's Principle, and Viscosity.
Crystalline Solids: Regular, repeating 3D pattern of particles. Sharp melting point. Anisotropic (properties vary with direction). Examples: NaCl, Diamond, Copper.
Amorphous Solids: No regular arrangement (random). No sharp melting point (soften over a range). Isotropic. Also called supercooled liquids. Examples: Glass, Plastic, Rubber.
Polymeric Solids: Long chains of repeating units (monomers). Intermediate structure. Low density. Examples: Polythene, Nylon.
Stress (σ): Force per unit area. Unit: Pascal (Pa). Types: Tensile, Compressive, Shear.
Strain (ε): Fractional change in dimension. Unitless. Types: Tensile, Volumetric, Shear.
Young's Modulus (Y): Ratio of Tensile Stress to Tensile Strain. Y = (F/A) / (ΔL/L).
Elastic Limit: Maximum stress a material can withstand without permanent deformation. Beyond this, Plastic Deformation occurs.
Energy stored in a deformed material. Determine from area under Force-Extension graph.
Formula: U = ½ F × Extension (For linear elastic region).
Streamline (Laminar) Flow: Smooth, regular flow where paths do not cross.
Turbulent Flow: Irregular, chaotic flow with eddies.
Equation of Continuity: Rate of flow is constant for incompressible fluid.
A₁v₁ = A₂v₂. (Conservation of Mass).
For an ideal fluid, sum of Pressure, K.E per unit volume, and P.E per unit volume is constant.
P + ½ρv² + ρgh = Constant.
Where speed is high, pressure is low.
Applications: Lift on airplane wings, Bunsen burner, Venturi meter, Torricelli's Theorem (Speed of efflux v = √2gh).
Viscosity (η): Internal friction of a fluid.
Stokes' Law: Drag force on a sphere: F = 6πηrv.
Terminal Velocity: Constant maximum velocity when Drag Force = Weight.
v_t = 2gr²ρ / 9η.