Fluid mechanics

• Fluid mechanics is the study of forces acting on a body travelling through air or water.
• 2 key factors act on a body 


  • Air resistance
  • Drag
• Air resistance acts on a body travelling at high velocity through the air
• Drag acts on a body travelling through the water.
• Air resistance and drag act in opposite direction to the direction of motion of the moving body.
• 4 factors that affect the magnitude of AR and drag

  1. Velocity
  2. Frontal cross sectional area
  3. Shape & streamlining
  4. Surface characteristics
• Factor affecting AR & Drag - Velocity 


  The greater the velocity, the greater the air resistance or drag. Velocity cannot be reduced to minimize air resistance or drag.
• Factor affecting AR & Drag - Frontal cross sectional area


  The larger the frontal cross sectional area the larger the air resistance or drag , so this must be minimised.
• Factor affecting AR & Drag - Shape & streamlining 


  The more streamlined and aerodynamic the shape of the body , the lower the air resistance or drag. This involves the creation of smooth airflow around the object.
• Factor affecting AR & Drag - Surface characteristics

  The smoother the surface the lower the air resistance or drag. This involves creating a smooth surface through clothing around the body.