sci_phy
Gravitation
Chapter summary, hard words and model exam answers for Class 9 Hindi.
Free online summary and notes (Class 9 Hindi). Read it here, no PDF download needed.
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Physics · ICSE Class 9
Summary
Newton's universal law says gravitational force is proportional to the product of the two masses and inversely proportional to the square of the distance between their centres.
In school numericals, if air resistance is ignored, all bodies fall with the same acceleration g at the same place.
Mass is measured in kilogram and remains almost the same from place to place. Weight is measured in newton and changes when g changes.
For ICSE Class 9, focus on the direction of change: g decreases with height above Earth and also decreases as we go below Earth's surface.
Gravitation provides the centripetal pull needed for orbital motion. This is conceptual here, not a Class 11 orbital calculation.
Hard words & meanings
| gravitation | Mutual attraction between any two masses |
| gravity | Earth's gravitational pull on bodies near it |
| free fall | Motion under gravity alone |
| gravitational constant | Constant G in Newton's law of gravitation |
| weight | Force of gravity on a body |
| acceleration due to gravity | Acceleration produced in a freely falling body by Earth's gravity |
Model exam answers, grammar & audio
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