Question

What is meant by Dynamic Stability ?

Answer 1

Hint:The basic definition of stability is that it is the measure of how likely it is for an object to topple over when pushed or moved. We can also say that stable objects are very difficult to topple over, while unstable objects topple over very easily.

Complete answer:
There are two basic types of stability- static stability and dynamic stability. Static stability is said to be the ability of a system to have a tendency of not returning to a steady state once all the disturbances have taken place. On the other hand, dynamic stability is said to be the ability of a system to return to a steady state once all the disturbances have taken place.

In other words we can say that when an object is referred to be in dynamic equilibrium, we mean to say that the object is in static stability. Similarly, we can say that when an object is referred to as being in static equilibrium, we mean to say that the object is in dynamic stability.

Further there are three subtypes of dynamic stability which are positive, neutral and negative dynamic stability.
Positive dynamic stability:An object with positive dynamic stability make oscillations that dampen out over time.
Neutral dynamic stability: An object with neutral dynamic stability makes oscillations that never dampen out over time.
Negative dynamic stability:An object with negative dynamic stability makes oscillations that gets worse with time.

Note:We often consider stability and equilibrium the same whereas there is a slight difference between the two terms. Stability is a measure of how likely it is for an object to topple over when pushed or moved whereas Equilibrium is the condition of a system when neither its state of motion nor its internal energy state tends to change with time.