Moments and Stability

• Mass is the amount of matter in an object.
• It is measured in kg.

• Weight is a force.
  
• The weight of an object depends on the mass of the object and gravity
• weight is measured in newtons.

MASS X 10 = WEIGHT

The centre of Gravity of an object is the point through which all the object's mass or weight appears to act.

To find the centre of gravity for a rectangle or any regular shaped obect draw digonals across it - where they intersect is the centre of gravity.

objective: to understand how levers work and what is ment by a "moment"

• A lever is a device to help you complete a task.
• all levers have a pivot and its position relative to the effort force and the load force determines how easily the lever enables us to carry out a task.
• the closer the pivot is to the load force the less effort force is needed.

The moment / turning effect depends on three things:

• The distance from the pivot
• the effort force
• the angle of force.

Moment = FORCE X DISTANCE FROM PIVOT

Force is measured in Newtons

Distance is measured in cm, m

Moment is measured in Ncm, Nm

Objective: To understand what the "principle of moments" is.

For a system to balance, the clockwisew moments must be equal to the anticlockwise moment.

Objective: to understand what is menat bythe stability of an object.

Two features that control the angle of toppling are:

• The height of the centre of gravity
• the area of the base

A low centre of gravity and a large base will prevent toppling.

if the centre of gravity is higher up, when tilted, the weight will act outside the object sooner.