Stability Flashcards
Stability
how difficult it is to tip an object over
What does stability depend on
- Base of Suppor
- Centre of Gravity (CoG)
- Line of Action of Weight
Base support
The area over which an object is in contact with the
ground. A wider base increases stability.
Centre of Gravity (CoG)
The point where the weight of the object appears to act. If the CoG is lower, the object is more stable.
Line of Action of weight
For an object to remain stable, the line of action of its weight must fall within its base of support. If it falls outside, the object will topple.
Types of stability
Stable Equilibrium
• Unstable Equilibrium
• Neutral Equilibrium
Stable Equilibrium:
When an object is displaced slightly and returns to its original position (e.g., a cone on its base).
Unstable Equilibrium
When an object is displaced and moves further from its original position (e.g., a cone on its tip).
Neutral Equilibrium
When an object is displaced slightly and stays in the new position (e.g., a ball on a flat surface).
What are the key factors affecting stability
• Height of Centre of Gravity
• Size of the Base
• Position of the CoG Relative to the Base
• Moment of a Force (Turning Effect)
Height of centre of gravity
Lowering the CoG increases stability. For example, crouching lowers the CoG in sports for better balance.
Size of the base
A wider base of support increases stability
Position of the CoG Relative to the Bas
If the CoG is over the base, the object is stable. If not, the object topples.
Moment of a force (turning effect)
Moment = force × Perpendicular Distance to the Pivot
