Resultant Forces

• What are free body diagrams used for?

  To find the resultant force on an object
• What do free body diagrams represent?

  All forces acting on a particular object
• How do we represent forces in free body diagrams?

  Using force arrows
• In a free body diagram of a plane, what does the forward arrow represent?

  The thrust of the plane
• What does the downward arrow in a free body diagram indicate?

  The weight of the object
• Why must forces in free body diagrams have both magnitude and direction?

  Because forces are vectors
• How is the magnitude of a force represented in a free body diagram?

  By the length of the arrows
• What happens to forces acting in different directions in a free body diagram?

  Some forces cancel each other out
• How do you calculate the resultant force in vertical components?

  By subtracting opposing forces
• What is the resultant force when there are equal forces acting up and down?

  Zero newtons overall
• If a plane has 120,000 newtons to the right and 90,000 newtons to the left, what is the resultant force?

  30,000 newtons to the right
• What happens to the resultant force if air resistance equals thrust?

  The horizontal resultant force is zero
• What does it mean if both horizontal and vertical components are balanced?

  The object is in equilibrium
• What are the steps to find the resultant force using free body diagrams?

  1. Identify all forces acting on the object.
  2. Represent each force with arrows.
  3. Calculate vertical and horizontal components separately.
  4. Subtract opposing forces to find resultant force.
  5. Determine overall resultant force from both components.
• What are the key components of a free body diagram for a plane?

  • Thrust (forward force)
  • Drag (backward force)
  • Weight (downward force)
  • Lift (upward force)