Stability

What is stability?

Stability refers to the ability of an object to return to its original position after it has been slightly tilted.

• Stability is the measure of a body’s ability to maintain its original position.

Stable Equilibrium

If a body returns to its original position after displacement and its CG returns to its original position, it is in a Stable Equilibrium.

• The tilted object will return to its original position.
• Line of action through its weight lies within its base.
• The Centre of gravity rises before falling back to the original height.

Unstable equilibrium

If a body continues to move away from its original position after being displaced or its CG continues to move, it is in an Unstable Equilibrium.

• The tilted object will move further away from its original position.
• Line of action through its weight lies outside its base.
• Centre of gravity is lowered and continues to go lower.

Neutral equilibrium

If a body remains wherever it is displaced or the CG remains at the same height, it is in a Neutral Equilibrium.

• Object stays in the position to which it is displaced.
• The lines of action through its weight and point of contact coincide.

Classic Stability Questions

How can an object be made more stable?

• Lowering its centre of gravity
• Increasing the area of its base