Chapter 11: Work and Energy – NCERT Exemplar Solutions for Class 9 Science
In this chapter, students learn about the concept of work in physics and how it differs from its everyday meaning. Work is defined as the product of force and displacement in the direction of force. The conditions for work to be done are clearly explained with examples. Students also learn about positive and negative work and situations where no work is done despite the application of force.
The chapter then introduces the concept of energy. Kinetic energy, which depends on the motion of a body, and potential energy, which is related to the position of a body, are discussed in detail. Derivations of their mathematical expressions are included, along with practical examples. The concept of the work-energy theorem is explained to show how work done on a body results in a change of its energy. Another major topic in this chapter is the principle of conservation of energy, which states that energy can neither be created nor destroyed, but only transformed from one form to another. Everyday life examples, such as a simple pendulum or falling objects, are used to illustrate this principle. NCERT Solutions for Class 9 Science help students understand the derivations, definitions, and numerical problems in a simplified manner. NCERT Exemplar Solutions for Class 9 Science provide additional higher-order thinking questions that enhance problem-solving skills and conceptual clarity. Together, these solutions make students confident in handling theoretical as well as numerical problems related to work and energy.