Chapter 7: Gravitation
NCERT Class 11 Physics, Part I, Chapter 7. 6 lessons, 13 narrated 3D videos, 6 simulations and 12 quiz questions, following the textbook section by section.
- Kepler’s lawsFor thousands of years people watched the planets wander across the night sky. Here is the sky over India, with Mars drifting slowly against the stars.
- The universal law of gravitationAn apple falls from a tree towards the Earth. The Moon goes round the Earth. Newton asked: could the same pull be doing both jobs?
- Acceleration due to gravityDrop a cricket ball from a balcony. It speeds up by 9.8 metres per second every second. Let us see where this number comes from.
- Gravitational potential energyLift a school bag onto a shelf. You do work against gravity, and the bag stores it as potential energy. Near the ground we write this as m g h.
- Escape speedThrow a ball straight up. It slows down, stops and falls back. Throw it faster and it goes higher before it returns.
- Satellites and their energyImagine a cannon on a very tall mountain, above the air. Fire a ball sideways. It curves down and lands some distance away.