NCERT Books on Class 11 Mechanical Properties of Solids

Introduction 

Mechanical Properties of Solids relate to the changes they undergo in the application of forces. 

Atoms or molecules in Solids are held together by interatomic or intermolecular forces and remain in an equilibrium position. To change/deform the shape or size of a body, a force is required to be applied. The property of the body which permits it to regain its original shape is known as elasticity and the deformation is referred to as elastic deformation. 

Substances that allow permanent deformation are known as plastics and the property is named plasticity. 

The elastic property of Solids has wide applications in engineering.

As per Hooke’s Law which governs this property, the elongation produced in a body is proportional to the applied force/load within the elastic limit.

Stress & Strain

When a deforming force is applied to a body, an equal restoring force is developed in the body. This restoring force is known as stress. The magnitude of stress developed is equal to F/A where F is the applied force and A is the area of the cross-section of the body. There are three types of stress namely, tensile stress, compressive stress, and tangential/shearing stress.  

The ratio of change in length to the original length of a solid due to applied force is known as longitudinal strain. On the other hand, a tangential force when applied to a body causes tangential/shearing stress to be developed and is expressed as the restoring force per unit area.  This causes shearing strain. As per Hooke’s Law, stress is proportional to strain. 

The Chapter on Class 11 Mechanical Properties of Solids also deals with stress/strain curves.  It also describes yield point or elastic limit and fracture point. Besides, it explains the modulus of elasticity which is the ratio of stress and strain for different materials. The Chapter in addition defines Young’s Modulus as well. 

Practical Applications of Mechanical Properties of Solids Mentioned in Chapter 9 of Class 11

Mechanical Properties of Solids have wide usage in engineering and science.  The property of elasticity is mostly used in the construction of bridges, beams, columns, pillars, etc. keeping also given their strength. The principle is also applied in the construction of cranes used for lifting heavy loads while ensuring that the extension of the rope used does not exceed the elastic limit of the rope. In the case of bridges, the designs have to ensure that the materials used don’t get deformed or break under heavy traffic or wind. 

How to study Chapter on Class 11 Mechanical Properties of Solids using NCERT Books?

Students can find plenty of study materials and download important guides on Class 11 Mechanical Properties of Solids on the Vedantu website. The website contains relevant questions, answers, and tips to solve question papers along with PDF links for the students.

NCERT Books are available on the Vedantu app as well to help you as a student to get the basics of the subject taught. 

The Vedantu website also contains revision notes which can be downloaded by the students to master the topics concerned.