chapter 5

• turning effect of a force

  also known as moment or torque

  is directly proportional to

  • perpendicular distance from the pivot where the force is applied
  • magnitude of the force applied
• to create a moment

  line of action of the force must not pass through the pivot
• principle of moments

  when the lever is balanced, forces acting on both sides of the pivot is the same
• principle of moments

  when the lever is balanced, forces acting on both sides of the pivot is the same
• conditions for equilibrium

  must not have any translational motion or rotational motion

  resultant moment of the body is zero

  resultant force of the body is zero
• stability


  the ability of an object to return to its original position

  can be affected by the position of the centre of gravity or the area of the base of the object
• position of centre of gravity

  the lower the centre of gravity of an object, the more stable it is

  the object with a higher centre of gravity will have a higher chance of toppling as compared to the object with lower centre of gravity. the vertical line through the centre of gravity of the object of higher centre of gravity will fall outside its base at a smaller tilt angle
• base area of an object

  the larger the base of an object, the more stable it is

  the object will smaller base area will topple first. this is because the verticle line through the centre of gravity of the object with smaller base area will fall outside its base at a smaller tilt angle