Chapter 1: Elasticity

Elasticity is the property of a material to return to its original shape after deformation. Stress (σ = F/A, unit: Pa) is force per unit area; strain is fractional deformation (dimensionless). Hooke's Law: within the elastic limit, stress ∝ strain. Three elastic moduli — Young's (Y, linear deformation), Bulk (B, volumetric deformation), Shear (G, tangential deformation) — all share dimensions [$M^{1}$ $L^{-1}$ $T^{-2}$] and unit Pa. The stress-strain curve sequence is: proportional limit → elastic limit → yield point → ultimate stress → breaking point. The slope of the linear region = Y. Compressibility = 1/B. NEET extension formula: $\Delta L$ = FL/(AY).

Chapter 2: Fluid Statics

Pascal's Law: pressure applied to an enclosed fluid is transmitted equally in all directions. Application: hydraulic press, $F_{1}$/$A_{1}$ = $F_{2}$/$A_{2}$. Pressure at depth h: P = $P_{0}$ + ρgh (Pa). This chapter is less frequently tested independently but supports Bernoulli's equation questions.

Chapter 3: Fluid Dynamics

For ideal, incompressible, non-viscous, streamline flow: Equation of continuity ($A_{1}$v_{1} = $A_{2}$v_{2}) ensures mass conservation — narrower pipe → higher speed. Bernoulli's equation (P + ½ρ$v^{2}$ + ρgh = constant) is energy conservation per unit volume. Key applications: Venturi meter, pitot tube, spray gun, airplane lift. Higher velocity → lower pressure.

Chapter 4: Viscosity and Terminal Velocity

Viscosity η: [$M^{1}$ $L^{-1}$ $T^{-1}$] (Pa·s). Newton's viscosity law: F = ηA(dv/dx). Stokes drag: F = 6πηrv. Terminal velocity v_t = 2$r^{2}$(ρ − σ)g/(9η). Key NEET result: v_t ∝ $r^{2}$. Poiseuille's law for pipe flow: Q = πr^{4}$$\Delta P/(8ηL) — flow rate depends on $r^{4}$ (radius to the fourth power).

Chapter 5: Surface Tension

S = F/L = Energy/Area; [$M^{1}$ $T^{-2}$] (N/m). Excess pressure — liquid drop: $\Delta P$ = 2S/R; soap bubble: $\Delta P$ = 4S/R (two surfaces). Capillary rise: h = 2S cosθ/(ρgr). Water-glass: acute θ → rise; Mercury-glass: obtuse θ → depression. Surface energy = S × $\Delta A$.

Chapter 6: Heat Transfer

Three modes — conduction (Fourier's law: Q/t = KA $\Delta T$/L), convection (Newton's cooling: dT/dt = −k(T − $T_{0}$)), radiation (Stefan-Boltzmann: P = σ$AT^{4}$, σ = $5.67 \times 10^{-8}$ W $m^{-2}$ $K^{-4}$). Thermal expansion: β = 3α (volume), 2α (area). T must be in Kelvin for radiation calculations.