Forces

• Moments = perpendicular distance*force applied
• Moments of couple forces = perpendicular distance*force of one couple
• Stress Equation


  σ = (F) / A
• Strain Equation


  ε = ΔL / L
• Modular Stress Equation


  σ = σtotal = (Ftotal) / A
• Absolute Pressure Equation


  p = F / A
• Gauge Pressure Equation


  p = ρgh
• A couple is two equal but opposite forces acting at right angles to each other, which produce no resultant force but do cause rotation.
• Pascal's principle


  F2/A2 = F1/A1
• Pascal's principle for a circular cross section: 


  $F₂ =$$F₁·d₁²/d₂²$
• When an object Is submerged into a fluid, the force of the water acts on it at right angles to the surface