Balanced moments

• What should you be able to calculate using balanced moments?

  Size of a force or its distance from the pivot
• What is a moment in physics?

  The turning effect of a force
• How is the moment calculated?

  Force multiplied by distance
• What must the distance be in relation to the pivot when calculating moments?

  Perpendicular from the pivot to the force line
• If person B applies a force of 315 Newtons at 0.76 meters, what is the clockwise moment?

  266 Newton meters
• What happens when a seesaw is balanced?

  • Clockwise moment equals anti-clockwise moment
  • Forces multiplied by their distances are equal
• How do you find the distance person A must sit from the pivot?

  Divide clockwise moment by person A's force
• How do you calculate the clockwise moment in the crane example?

  Multiply force by distance from pivot
• How do you find the force applied by the counterweight?

  Divide anti-clockwise moment by distance
• What is the distance from the pivot to the counterweight in the crane example?

  10 meters
• Why do certain objects topple?

  • Weight acts down from center of mass
  • Line of action moves outside the base
  • Resultant unbalanced moment causes toppling
• What does the weight of the block represent?

  Force due to gravity
• What happens when the block is tilted?

  Line of action may move outside the base
• What is the resultant effect when the line of action lies outside the base?

  Unbalanced moment causing the block to topple