Physics · Mechanical Properties Of Solids · NEET
A short, thick block would simply be compressed a little. But a long, thin column is unstable under a pushing (compressive) load. Beyond a critical load the column cannot stay straight, so it suddenly bows out to the side. This sideways bending is buckling. It happens because a slender column bends far more easily than it compresses, so it fails by bending, not by crushing. NEET tests this as a conceptual application, not a numerical value.
NCERT Fig 8.9 shows two designs. A pillar with rounded ends (like two hinges) can pivot at both ends, so it buckles easily and supports LESS load. A pillar with distributed or flared ends spreads the load over a wider base and holds the ends firmly, so it resists buckling and supports MORE load. This is why real building and bridge columns are made wider and flared where they meet the floor and roof.
Both matter, but slenderness (the length-to-thickness ratio) is the key. A long, thin column buckles at a small load, while a short, thick column of the same material can take a much larger load before buckling. That is why tall support columns are made thick and often flared, not thin. For NEET, remember: longer and thinner means easier buckling.
Buckling is always caused by a compressive load, meaning a load that pushes the two ends of the column toward each other along its length. A pillar or column carries the weight of the structure above it, so it is in compression. A wire hanging with a weight, by contrast, is in tension and simply stretches; it does not buckle.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Yes. It appears in the 'Elastic Behaviour of Materials' application section of the Mechanical Properties of Solids chapter in NCERT Class 11 Physics. It is usually tested as a conceptual or assertion-reason question, not as a numerical.
Wider, distributed ends resist buckling and support a larger load than rounded ends. Spreading the load and firmly fixing the ends stops the column from bending out sideways under compression.
A beam is loaded across its length (a transverse load) and it bends or sags, which is why I-shaped sections are used. A column is loaded along its length (a compressive load) and it buckles or bows sideways when it is long and thin.
Less. Rounded ends behave like hinges and buckle at a lower load, so distributed-end pillars are stronger and are preferred in construction.
