Chapter 9:  Solids and Fluids

 1. Elasticity-        strain proportional to stress

                             Young's modulus ( y )  -  stress / strain

  2. Density (r)         r =  M/V  ( Kg/m³)

      Pressure (P)    P = F/A      (N/m²)

    Pressure with depth     P = P₀ +  rgh   where P₀ is the pressure on the surface of the fluid and P₂ the pressure at a depth h

    Pascal's principle- same change in pressure  is felt  through out  an enclosed fluid. 

2. Archimedes' principle-   the buoyant force experienced by an immersed object is equal to the weight of the fluid displaced

                                               F_B =  r_fVg

3. Fluids in motion-  steady (streamline flow) and unsteady flow

   Equation of continuity- mass flow rate is the same every where through a pipe of differing cross sections.

                                         r₁A₁v₁ = r₂A₂v₂

   For incompressible fluids  r₁ = r₂;     gives A₁v₁ = A₂v₂

  Bernoulli's equation-   based on work-energy theorem and conservation of energy

  For a fluid flowing through a pipe of differing cross sections and elevations

          P₁ + ½ rv₁² + rgy₁  =      P₂ + ½ rv₂² + rgy₂

 Applications of Bernoulli's equation