Resultant forces

• What are free body diagrams used for?

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

  They show all the forces acting on a particular object
• How do we represent forces in free body diagrams?

  Using force arrows
• In the example of a plane, what forces are represented in its free body diagram?

  Thrust, air resistance, weight, and lift
• Why do forces need 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
• How do you calculate the resultant force from multiple forces?

  By considering the forces in different directions separately
• In the vertical component example, what is the resultant force when there is an upward force of 80,000 newtons and a downward force of 80,000 newtons?

  0 newtons
• What is the resultant force in the horizontal component when there is a force of 120,000 newtons to the right and 90,000 newtons to the left?

  30,000 newtons to the right
• What happens to the resultant force if air resistance equals 120,000 newtons in the horizontal component?


  The horizontal resultant force would be 0 newtons
• What does it mean when both horizontal and vertical components are perfectly 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 showing direction and magnitude.
  3. Calculate the resultant force in the vertical direction.
  4. Calculate the resultant force in the horizontal direction.
  5. Combine the results to find the overall resultant force.