Post by Admin on Nov 24, 2016 9:56:23 GMT
Moments
• The measure of the turning effect of a force is called the moment of the force.
• Moment of a force = (force) x (perpendicular distance between the force and the fulcrum).
• Fulcrum: the fixed point or line through which something swings.
• Moments can be increased by increasing the size or the force or increasing the distance between the force and the fulcrum.
Levers
• A lever is any rigid body that is free to turn around a fixed point or axis called a fulcrum.
Law of the Lever
• When a lever is balanced by any number of forces, the sum of the clockwise moments equal to the sum of the anti-clockwise moments.
Centre of Gravity
• This is the point in a body where all its weight appears to act.
• The c.o.g. of a regularly shaped symmetrical objects are at their centre.
• The position of an object’s centre of gravity (c.o.g.) determines the stability of an object.
• A low centre of gravity makes an object more stable.
• A high centre of gravity makes an objects less stable.
• *A wide base increases stability, a narrow base decreases stability.*
• A body will topple if a vertical line through its c.o.g. falls outside its base.
Equilibrium
• A body is in stable equilibrium if, when moved slightly its c.o.g. rises.
• A body is in unstable equilibrium if, when moved slightly its c.o.g. falls.
• A body is in neutral equilibrium if, when moved slightly its c.o.g. doesn’t move.
• The measure of the turning effect of a force is called the moment of the force.
• Moment of a force = (force) x (perpendicular distance between the force and the fulcrum).
• Fulcrum: the fixed point or line through which something swings.
• Moments can be increased by increasing the size or the force or increasing the distance between the force and the fulcrum.
Levers
• A lever is any rigid body that is free to turn around a fixed point or axis called a fulcrum.
Law of the Lever
• When a lever is balanced by any number of forces, the sum of the clockwise moments equal to the sum of the anti-clockwise moments.
Centre of Gravity
• This is the point in a body where all its weight appears to act.
• The c.o.g. of a regularly shaped symmetrical objects are at their centre.
• The position of an object’s centre of gravity (c.o.g.) determines the stability of an object.
• A low centre of gravity makes an object more stable.
• A high centre of gravity makes an objects less stable.
• *A wide base increases stability, a narrow base decreases stability.*
• A body will topple if a vertical line through its c.o.g. falls outside its base.
Equilibrium
• A body is in stable equilibrium if, when moved slightly its c.o.g. rises.
• A body is in unstable equilibrium if, when moved slightly its c.o.g. falls.
• A body is in neutral equilibrium if, when moved slightly its c.o.g. doesn’t move.