Couples

• What is a couple in physics?

  A pair of equal and opposite forces

  
• What are the characteristics of a couple?

  Equal in magnitude, opposite in direction
• How are the forces in a couple oriented relative to each other?

  Perpendicular to the distance between them
• What is required for a couple to exist?

  Two equal and opposite forces separated by distance
• What is the resultant force of a couple?

  Zero
• How does Newton's Second Law relate to a couple?

  The object does not accelerate
• How does the moment of a couple differ from a single force?

  It doesn’t depend on a pivot
• What is the formula for the moment of a couple?

  Force × Perpendicular distance
• What are the conditions for forces to act as a couple?

  • Forces must be equal in size
  • Forces must be in opposite directions
  • Forces must be perpendicular to the distance between them
• Why is option B incorrect in identifying a couple?

  The forces are in the same direction
• Why is option C incorrect in identifying a couple?

  The forces are different in size
• Why is option D incorrect in identifying a couple?

  The distance between the forces is not perpendicular
• What is a key tip regarding the line of action of forces in a couple?

  • Forces cannot share the same line of action
  • They must act at different points