Mechanical Engineering - Engineering Mechanics - Discussion

It should be neutral equilibrium. Equilibrium has three types: stable, unstable and neutral. Stable equilibrium is the condition when a small disturbance is given it try to come into the original position.

In case of unstable equilibrium object will never come into equilibrium position when given a small disturbance. Neutral equilibrium is the condition when object comes to a new equilibrium condition when given a small disturbance. This is is the third case.

1. An equilibrium is considered stable if the system returns to it after small disturbances.

2. If the system moves away from the equilibrium after small disturbances, then the equilibrium is unstable, and.

3. The neutral equilibrium is that when moved slightly, it neither tends to return to its former position not depart more widely from it.

So 2nd option best fits, :).

@Manali.

If force is zero then by 1st law of newtons, it will remain stationary or in motion until unless applied any external force on it so due to this it must be in stable position.

Or one reason more, force is zero then it will be in equilibrium because if we will consider all forces then it should be in equal and opposite hence it also must be in stable position.

Actually for justify stability we consider all possible way of cylinder and we see here it is kept on floor by means of convex surface so if we apply small disturbance then it will roll on the floor but if we kept it vertically on base then it will be stable so it is unstable.

It depends on the surface on which the cylinder is lying.
If it lies on the concave surface then it will be in stable equilibrium.
If it lies on convex surface then it will be in unstable equilibrium.
If it lies on the plane surface then it will be in neutral equilibrium.

It's neutral equilibrium A ball rolling, are cylinder rolling are both examples of neutral equilibrium where a new equilibrium condition is adopted without change in the position of C.G.

So neutral equilibrium is the correct option.

@Denim Jeans.

Here it is a smooth surface, So the coefficient of friction is zero.

F = n*R.

Where, R = normal force.

n = coefficient of friction.
F = force applied.

Then,
If n=0 F=0.

i.e it cannot be stable.

It is not neutral because when disturb it does not return to its initial position and center of gravity is lower while it return and center of gravity is unchanged in neutral equilibrium.

If the particle is slightly displaced from its orignal position and it doesnt come back to its initial position then its unstable equilibrium, so in the case of convex surface.

Well it simple cause the surface of that is talk about is the convex surface and it is not a plane nor smooth surface. And therefore the cylinder cannot be stable.