P2.7 Resultant forces & free body diagrams

• What are free body diagrams used for?

  To show forces acting on an object
• How do we represent forces in free body diagrams?

  Using force arrows indicating direction and magnitude
• What does the length of a force arrow represent?

  The magnitude of the force in newtons
• What happens to forces acting in opposite directions in a free body diagram?

  Some forces cancel each other out
• What is the resultant force?

  The overall force acting on an object
• How do you calculate the resultant force in vertical components?

  By subtracting opposing forces from each other
• In the example, what were the vertical forces acting on the plane?

  80,000 newtons up and down
• What is the resultant force for the vertical component in the example?

  Zero newtons overall
• What were the horizontal forces acting on the plane?

  120,000 newtons to the right and 90,000 newtons to the left
• What is the resultant force for the horizontal component in the example?

  30,000 newtons to the right
• What would happen if air resistance was 120,000 newtons?

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

  The object is in equilibrium
• What is the overall resultant force when the object is in equilibrium?

  No resultant force acting on it
• What are the steps to find the resultant force using free body diagrams?

  1. Identify all forces acting on the object
  2. Draw arrows to represent each force
  3. Determine the magnitude and direction of each force
  4. Calculate the resultant force by considering horizontal and vertical components separately
  5. Analyze if the object is in equilibrium or not