NCERT Exemplar Solution for Class 9 Science Chapter-10 Gravitation
Gravitation is one of the most interesting chapters in Class 9 Science because it explains the invisible force that keeps planets moving around the Sun and objects attached to the Earth. This chapter introduces students to the universal law of gravitation, free fall, thrust, pressure, buoyancy, and relative density. It connects scientific theory with practical experiences such as why objects fall downward, why ships float on water, and how astronauts experience weightlessness in space. The NCERT Exemplar Solution for Class 9 Science helps students understand these important concepts through application-based questions and logical explanations. By practicing questions from the NCERT Exemplar Solution, learners can improve conceptual clarity and perform better in examinations.
Find the Exercises PDF of NCERT Exemplar Solution for Class 9 Science Chapter-10 Gravitation
Universal Law of Gravitation
The chapter begins with the concept of gravitation and explains how every object in the universe attracts every other object with a certain force. This attraction depends on the masses of the objects and the distance between them. Sir Isaac Newton introduced the universal law of gravitation after observing natural phenomena like falling apples and planetary motion.
The mathematical expression for gravitational force is:
F = G{m1m2}/{r^2}
Students learn that gravity is responsible for keeping planets in orbit, holding the atmosphere around Earth, and causing tides in oceans.
Important concepts covered in this chapter include:
- Universal law of gravitation
- Gravitational force between objects
- Free fall and acceleration due to gravity
- Mass and weight
- Thrust and pressure
- Buoyancy and Archimedes’ principle
- Relative density
- Floating and sinking of objects
- Motion of planets and satellites
These concepts help students understand how gravity influences life and natural events on Earth.
Free Fall, Mass, and Weight
Free fall refers to the motion of an object when gravity is the only force acting on it. Students learn that all objects fall toward Earth with the same acceleration due to gravity, represented by:
g = 9.8,m/s^2
The chapter also explains the difference between mass and weight. Mass remains constant everywhere, while weight changes depending on gravitational force. Weight is calculated using the formula:
This section is important because students often confuse mass with weight. Exemplar questions help them understand the practical applications of these terms through numerical and conceptual exercises.
Buoyancy and Archimedes’ Principle
One of the most interesting topics in this chapter is buoyancy. When an object is placed in a liquid, the liquid exerts an upward force called buoyant force. This explains why some objects float while others sink.
Archimedes’ principle states that a body immersed in a fluid experiences an upward force equal to the weight of the fluid displaced by it. This principle is widely used in designing ships, submarines, and hydrometers.
Students also learn about relative density, which compares the density of a substance with the density of water. These concepts are explained through real-life examples, making the chapter easier to understand and remember.
Importance of NCERT Exemplar Questions
The NCERT Exemplar Solution for Class 9 Science is highly useful for strengthening problem-solving abilities. The questions included in exemplar exercises focus on logical thinking and practical understanding rather than simple memorization.
Benefits of practicing exemplar questions include:
- Better understanding of gravitation concepts
- Improvement in numerical problem-solving
- Strong preparation for school exams
- Practice with higher-order thinking questions
- Enhanced analytical and reasoning skills
- Better understanding of real-life applications of gravity
Regular revision and practice help students build confidence and accuracy in solving Physics-based questions.
Conclusion
Gravitation is a foundational chapter that explains how forces act between objects in the universe. From planetary motion to floating objects, the chapter covers many important scientific principles that students observe in daily life. The NCERT Exemplar Solution provides additional practice that helps learners understand formulas, numerical problems, and conceptual applications more effectively. With proper study and regular practice, students can easily master the chapter and improve their overall performance in Science examinations.