Question Answer
Gravitation Question Answer Practice
Gravitation question answer practice for Class 9 Science revision.
4-minute audio preview
FAQ
Why does the Moon not fall onto the Earth?
The Moon is continuously falling toward Earth due to gravity but also moves sideways fast enough to keep revolving around Earth instead of crashing. You can listen to the full explanation on Harshali Academy.
Does gravity act only between Earth and the Moon?
No, gravity acts between every two objects in the universe, but the force is noticeable only when masses are large or distances are small. Harshali Academy’s lessons explain this clearly.
Why does weight change on the Moon but mass remains the same?
Weight depends on gravity, which is weaker on the Moon, so weight decreases. Mass is the amount of matter and does not change with location. Harshali Academy covers this concept in detail.
What is centripetal force and how is it related to gravitation?
Centripetal force is the inward force that keeps an object moving in a circular path. In space, gravity acts as the centripetal force pulling the Moon toward Earth, keeping it in orbit. Harshali Academy explains this with examples.
How can a heavy steel ship float on water?
A ship floats due to buoyant force, the upward force exerted by water, which balances the ship’s weight. This concept is linked to gravitation and is explained in the chapter on Harshali Academy.
Important exam questions with answers
What is gravitation?
Gravitation is the force of attraction between any two objects in the universe. It pulls objects toward each other, like the Earth pulling an apple down. (2 marks)
On what factors does gravitational force depend?
Gravitational force depends on the masses of the two objects and the distance between them. Larger masses increase force, and greater distance decreases it. (2 marks)
Differentiate between mass and weight.
Mass is the amount of matter in an object and remains constant everywhere; its unit is kilogram. Weight is the force with which Earth pulls an object, depends on gravity, and is measured in newtons. (3 marks)
Key concepts from this chapter
- Gravitation is the force of attraction between any two objects in the universe.
- Newton’s Universal Law of Gravitation states that gravitational force depends on masses and distance between objects.
- Gravitational force pulls objects toward the Earth, giving them weight.
- Mass is constant and does not change with location; weight depends on gravitational acceleration.
- The Moon revolves around the Earth due to the balance of gravitational pull and its sideways motion (inertia).
Question-answer focus
Imagine sitting under a big tree on a calm afternoon, watching an apple fall to the ground. This simple scene from the chapter Gravitation sparks a powerful question asked by Isaac Newton: why does the apple fall down instead of sideways or upward? The chapter Gravitation on Harshali Academy explores this question deeply, explaining how the force of gravity pulls objects toward each other, from apples to the Moon. Harshali Academy’s detailed audio lessons help students understand the universal law of gravitation, the difference between mass and weight, and why planets orbit the Sun instead of drifting away. This chapter is essential for Class 9 Science learners aiming to grasp fundamental physics concepts. This question-answer page helps students practise likely doubts and exam responses from Gravitation before downloading the full app.
Hindi explanation
कल्पना करो कि तुम एक बड़े पेड़ के नीचे बैठे हो और अचानक एक सेब जमीन पर गिरता है। यह साधारण घटना गुरुत्वाकर्षण अध्याय की शुरुआत है। इस अध्याय में हम समझेंगे कि पृथ्वी सेब को नीचे क्यों खींचती है और चंद्रमा पृथ्वी के चारों ओर कैसे घूमता है। यह ज्ञान कक्षा 9 के विज्ञान के लिए बहुत महत्वपूर्ण है।
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