A cone resting on its apex is an example of

Options

A. unstable equilibrium.
B. stable equilibrium.
C. neutral equilibrium.
D. None of these

Explanation

To solve the question "A cone resting on its apex is an example of," we need to analyze the situation of the cone and the forces acting on it.

### Step-by-Step Solution:

1. **Understanding the Position of the Cone**:
- A cone resting on its apex means that the pointed end (the apex) is on the ground, and the wider base is facing upwards.

**Hint**: Visualize the cone standing on its tip to understand its stability.

2. **Identifying the Center of Gravity**:
- The center of gravity of the cone is located along the vertical line that passes through its apex. When the cone is perfectly upright, the center of gravity is directly above the apex.

**Hint**: Remember that the center of gravity is the point where the weight of the object is considered to act.

3. **Analyzing Forces**:
- The forces acting on the cone include the gravitational force (acting downwards through the center of gravity) and the normal force (acting upwards at the apex). In this position, these forces are balanced.

**Hint**: Think about how forces need to balance for an object to remain at rest.

4. **Considering Torque**:
- Since both the gravitational force and the normal force act through the apex, there is no distance between the line of action of these forces and the apex. Therefore, no torque is generated, and the cone remains in equilibrium.

**Hint**: Recall that torque is generated when a force is applied at a distance from a pivot point.

5. **Effect of Displacement**:
- If the cone is slightly tilted, the center of gravity shifts to one side. The gravitational force will no longer act directly through the apex, creating a torque that will cause the cone to fall over.

**Hint**: Consider what happens when the center of gravity moves away from the apex.

6. **Conclusion on Stability**:
- Since a slight disturbance can cause the cone to topple, we conclude that the cone resting on its apex is in an unstable equilibrium.

**Hint**: Think about how stability is defined in terms of equilibrium and response to disturbances.

### Final Answer:
A cone resting on its apex is an example of **unstable equilibrium**.