What is gravitation class 9?

In Class 9 Physics (NCERT), gravitation is introduced as a natural phenomenon of attraction between any two objects with mass. The chapter “Gravitation” explains it in simple terms: any two bodies in the universe attract each other with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. This is mathematically expressed by Newton’s Law of Gravitation.

For students, gravitation in Class 9 is not just a definition but a concept with practical applications. It is the reason objects fall towards Earth, why we have a stable atmosphere, and why planets revolve around the Sun. Gravitation also helps explain phenomena such as free fall, acceleration due to gravity, and motion of celestial bodies.

In NCERT Class 9, the following key concepts are taught:

• Gravitational force: The measurable force of attraction between two masses.
• Free fall: Motion of objects under the influence of Earth’s gravity alone, without air resistance.
• Acceleration due to gravity (g): On Earth, g=9.8 m/s2 It is constant near Earth’s surface.
• Mass vs. Weight: Mass is the amount of matter in a body (constant everywhere), while weight is the gravitational force exerted on the body by Earth (variable depending on location).
• Thrust and Pressure: Applications of gravitational concepts in fluids.

The NCERT syllabus emphasizes that gravitation is universal—it affects everything from the smallest particle to the largest galaxy. For example, the same gravitational force that causes a stone to fall also governs the motion of the Moon around the Earth.

The Class 9 gravitation chapter also includes important experiments and applications:

• The concept of buoyancy and Archimedes’ principle.
• Why objects feel lighter in water.
• Real-life applications such as designing ships and submarines.

By learning gravitation in Class 9, students build a foundation for advanced studies in physics, astronomy, and engineering. They also understand the role of forces in everyday life, making it both a theoretical and practical concept.