13 Unstable Equilibrium Example: Detailed Explanations

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In this article on physics, we will understand the practical unstable equilibrium examples and their related concepts facts.

Unstable equilibrium takes place when a body gains maximum gravitational potential energy. When a tiny amount of force is applied to any substance or object, it travels away from its original position to make the system in unstable equilibrium. The unstable equilibrium examples are inverted objects.

Now to understand the detailed explanations of the Unstable equilibrium example.

Inverted pencil

Place a pencil in its inverted position. It will not stay in the same position for more than a second because it gains more gravitational potential energy and will be in unstable equilibrium. Hence any pointed object, when placed inverted, will be an unstable equilibrium example.

Basket-ball

At some point in the game, when the player tries to put the ball in the basket, there will be a chance that that ball stays on the edge of the basket; it tries to balance and later rolls down due to gain in maximum gravitational potential energy. It makes the basket-ball reach unstable equilibrium and is an unstable equilibrium example.

unstable equilibrium example
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Ice cube

Due to heat, the solid ice-cube melts and becomes liquid and flows on the surface. Here it is essential to notice that the liquid form of ice will be in unstable equilibrium. We can infer that after changing its state to liquid, the solid matter will be an unstable equilibrium example.

unstable equilibrium example
 
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An object placed at the edge of any table

When you place any object or material at the edge of any solid substance, at some point, it will surely fall. It happens because it gains more gravitational potential energy as the object goes from its position. It shifts from its original position reaching unstable equilibrium.

unstable equilibrium example
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Vertical Pendulum

If you keep the pendulum in its vertical position, it won’t stay in that position for a long time without any rigid support. It moves from its previous position and reaches the floor as soon as it possesses more gravitational potential energy. It reaches its unstable equilibrium and is a primary unstable equilibrium example.

Inverted Pointed objects

Place a pencil in its inverted position. It will not stay in the same position for more than a second because it gains more gravitational potential energy and will be in unstable equilibrium. Hence any pointed object, when placed inverted, will be an unstable equilibrium example.

The ball is placed at the edge of any material

When you keep a ball at any edge, it tries to balance for some time, and later it reaches the ground. It takes place due to the more gravitational potential energy possessed by the ball at the centre of gravity, making it lose its balance and reach the ground. It is an unstable equilibrium example.

unstable equilibrium example
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Movement of marbles

When you throw a pack of marbles on the floor, it moves randomly without staying in a stable position due to force. The movement of these marbles will occur due to the gain in more gravitational potential energy when thrown. It will be in its unstable equilibrium and is an unstable equilibrium example.

Sliding of objects

Sliding objects or any material can also be considered an unstable equilibrium example. When you make any material slide on the surface, it slides down quickly without facing any hurdles in some cases. At the same time, sliding for every point, the position changes that, making the object be in its unstable equilibrium by gaining more potential energy.

unstable equilibrium example
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Birthday cap kept on any book

We know that the birthday cap is of the shape of the mathematical object cone. So, if we see the shape of the cone, it has one sharp inverted point. If you try to keep that cap inverted on any apex part of the book, it loses its control and moves away from its position, gaining more gravitational potential energy. At this point, the birthday cap will be in unstable equilibrium.

Frame placed with delicate support

When you try to hang a frame on a delicate nail, it won’t stay in the same position for more time, and it falls due to the instability of the frame on the nail. It is because the object gains more gravitational potential energy that makes it reach the unstable equilibrium.

unstable equilibrium example
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Paper ball on any surface

Playing with chunks of the paper ball was the all-time favourite game for many people. When you throw a paper ball, it reaches the ground and stays there till further force is applied. After applying the force, it moves far from its position by gaining more potential energy; at this time, it reaches its unstable equilibrium. It is an excellent unstable equilibrium example.

unstable equilibrium example
Image Credit: Pixabay free images

Inverted pen

Place a pen in its inverted pointed position. It will not stay in the same position for more than a second because it gains more gravitational potential energy, moves from its position, and collapses. It will reach its unstable equilibrium. Hence any pointed object, when placed inverted, will be an unstable equilibrium example.

Read more: Stable equilibrium example

Frequently Asked Questions on Unstable Equilibrium | FAQs

What do you mean by the term unstable equilibrium?

We can say that any substance is in unstable equilibrium when the centre of gravity of that material decreases.

When a tiny amount of push or pull is applied to any stationary material, it travels from that place. When its centre of gravity decreases and gains a significant amount in its potential energy.

What can be a daily life example of material in unstable equilibrium?

In daily routine, we can observe many examples of unstable equilibrium, even the minute objects we see around us are in an unstable equilibrium state.

A small grain of seed that fails to maintain its balance and spreads on the floor is unstable equilibrium; a ball that rolls down the lane when disturbed is the important unstable equilibrium example.

How do you get to know if the object in equilibrium is unstable?

We know that any system is in its unstable equilibrium by observing its movement when it undergoes disturbance.

Any material is considered in unstable equilibrium when it does not come back to the initial position before disturbance. Even for a small amount of force applied or disturbance, the system changes its equilibrium state from stable to unstable.

What are the main conditions for an unstable equilibrium?

The main conditions for an unstable equilibrium are,

  • The total net force or disturbance the system experiences.
  • The movement of the system when it gets disturbed.
  • Reduction in centre of gravity
  • Increase in potential energy
  • The movement from the system in equilibrium position.

What situation may lead to an unstable equilibrium?

The situations that may lead the system to unstable equilibrium depend on its balance, movement, and force applied.

Even if for a slight push or pull, the object gets disturbed and goes to some other position and does not return to its initial position, it may cause that system of objects to be in unstable equilibrium.

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