AHSEC Class 11 Physics Chapter 7 Gravitation Notes (2026–27) – Assam Eduverse
The AHSEC Class 11 Physics Chapter 7 Gravitation Notes (2026–27) are prepared strictly according to the latest AHSEC/ASSEB syllabus for Assam Board students. These AHSEC Class 11 Physics Chapter 7 Gravitation Notes cover all important concepts including Newton’s Law of Universal Gravitation, gravitational field, acceleration due to gravity (g), escape velocity, orbital velocity, and satellite motion.
Prepared by subject experts of Assam Eduverse, these ahsec class 11 physics gravitation notes provide clear explanations, step-by-step derivations, and exam-focused theory. The ASSEB class 11 physics chapter 7 notes help students understand Kepler’s Laws of Planetary Motion, gravitational potential energy, and variation of g with height and depth in a simple and structured format.
Regular revision using these AHSEC Class 11 Physics Chapter 7 Gravitation Notes, along with important ahsec class 11 gravitation formulas and assam board class 11 physics gravitation notes, strengthens conceptual clarity and improves numerical-solving skills for the 2026–27 board examination.
AHSEC Class 11 Physics Chapter 7 Gravitation Notes – Assam Board 2026–27 Complete Guide
1. Introduction
- ★We observe from daily life that objects fall toward Earth. This shows that Earth attracts objects. This attractive force between masses is called gravitation.
- ★Galileo proved that all bodies fall with the same constant acceleration irrespective of their mass (ignoring air resistance).
- ★Development of Universe Models:
- Ptolemy – Geocentric model (Earth at centre).
- Copernicus – Heliocentric model (Sun at centre).
- Tycho Brahe – Accurate planetary data.
- Johannes Kepler – Three laws of planetary motion.
- Isaac Newton – Universal Law of Gravitation.
2. Kepler’s Laws
Law of Orbits
- ★Planets move in elliptical orbits with Sun at one focus.
- ★Ellipse: closed curve formed using two fixed points (foci).
- ★Circle is special case when both foci merge.
Law of Areas
- ★Planet sweeps equal areas in equal intervals of time.
- Faster near Sun (perihelion), slower far from Sun (aphelion).
- Due to conservation of angular momentum.
Law of Periods
- ★
T² ∝ a³ - ★T²/a³ = constant for all planets.
3. Universal Law of Gravitation
- ★Every body attracts every other body in the universe.
F = G m₁m₂ / r²- Directly proportional to masses.
- Inversely proportional to square of distance.
- Always attractive.
- Acts along line joining centres (central force).
- Obeys Newton’s third law.
- Follows superposition principle (net force = vector sum).
4. Gravitational Force for Extended Bodies
- Hollow Spherical Shell:
- Outside → behaves as if entire mass at centre.
- Inside → gravitational force is zero.
- Solid Sphere:
- Outside → behaves as if entire mass at centre.
- Inside → only mass within that radius contributes.
- Force ∝ distance from centre.
5. Gravitational Constant (G)
- Measured by Henry Cavendish (torsion balance experiment).
G = 6.67 × 10⁻¹¹ N m²/kg²- Universal constant.
6. Acceleration Due to Gravity (g)
g = GMₑ / Rₑ²- Value ≈ 9.8 m/s².
- Depends on Earth's mass and radius.
7. Variation of g with Height
g(h) = GMₑ/(Rₑ + h)²- For small h:
g(h) ≈ g(1 − 2h/Rₑ) - g decreases with height.
8. Variation of g with Depth
g(d) = g(1 − d/Rₑ)- g decreases with depth.
- Maximum at surface.
9. Gravitational Potential Energy
- Near surface:
PE = mgh - General form:
PE = − GMm / r - Negative sign shows attractive force.
- Gravitational force is conservative (work done independent of path).
10. Gravitational Potential
- Potential energy per unit mass.
V = − GM / r- Total potential energy of system = sum of all pair interactions.
11. Escape Speed
- Minimum speed required to escape gravitational field permanently.
vₑ = √(2GMₑ / Rₑ)vₑ = √(2gRₑ)- For Earth ≈ 11.2 km/s.
- Independent of mass of object.
12. Earth Satellites
- Satellite revolves due to gravitational force.
V = √(GMₑ / r)T = 2πr / VT² ∝ r³- Near Earth: T ≈ 85 minutes.
13. Energy of Orbiting Satellite
KE = GMₑm / 2rPE = − GMₑm / rTotal Energy = − GMₑm / 2r- Total energy negative (bound system).
- |PE| = 2 × KE.
- If total energy ≥ 0 → body escapes.
14. Important Properties of Gravitation
- Central force.
- Inverse square law.
- Conservative force.
- Angular momentum conserved.
- No gravitational shielding possible.
15. Special Results
- Outside spherical body → mass acts at centre.
- Inside hollow shell → force = 0.
- Inside solid sphere → force ∝ distance.
16. Complete Formula List
F = Gm₁m₂ / r²g = GMₑ / Rₑ²g(h) = GMₑ / (Rₑ + h)²g(d) = g(1 − d/Rₑ)PE = − GMm / rV = − GM / rvₑ = √(2gRₑ)V = √(GMₑ / r)Total Energy = − GMₑm / 2r
AHSEC Class 11 Physics Chapter 7 Gravitation Notes for Assam Board 2026–27
The AHSEC Class 11 Physics Chapter 7 Gravitation Notes are prepared strictly as per the latest AHSEC/ASSEB syllabus 2026–27. These AHSEC Class 11 Physics Chapter 7 Gravitation Notes explain all fundamental concepts of gravitation in a clear and exam-focused manner for Assam Board students.
Students must carefully study these ahsec class 11 physics gravitation notes to understand important topics like Newton’s Law of Universal Gravitation, gravitational constant (G), acceleration due to gravity (g), variation of g with height and depth, and gravitational potential energy. The ASSEB class 11 physics chapter 7 notes also include detailed explanations of Kepler’s Laws of Planetary Motion.
All important derivations such as escape velocity, orbital velocity, and time period of satellites are clearly explained in these AHSEC Class 11 Physics Chapter 7 Gravitation Notes. Key ahsec class 11 gravitation formulas are highlighted for quick revision and better numerical practice.
Regular revision using these AHSEC Class 11 Physics Chapter 7 Gravitation Notes along with assam board class 11 physics gravitation notes strengthens conceptual clarity and improves performance in theory as well as numerical-based questions for the 2026–27 examination.
Frequently Asked Questions (FAQ)
1. Are these AHSEC Class 11 Physics Chapter 7 Gravitation Notes based on the latest syllabus?
Yes, these AHSEC Class 11 Physics Chapter 7 Gravitation Notes follow the latest AHSEC/ASSEB syllabus for 2026–27.
2. Do these notes include important derivations?
Yes, these ahsec class 11 physics gravitation notes include important derivations like escape velocity and orbital velocity.
3. Are important formulas included in these notes?
Yes, all key ahsec class 11 gravitation formulas are clearly listed for quick revision and exam preparation.
4. Are these notes helpful for numerical problem solving?
Yes, these assam board class 11 physics gravitation notes improve conceptual clarity and numerical-solving skills.
5. What topics are covered in Chapter 7 Gravitation?
Topics include Newton’s Law of Gravitation, acceleration due to gravity, gravitational potential, escape velocity, orbital velocity, and Kepler’s laws.
6. Are these notes suitable for ASSEB board exams?
Yes, these ASSEB class 11 physics chapter 7 notes are designed specifically for Assam Board exam preparation.
7. Who prepared these AHSEC Class 11 Physics Chapter 7 Gravitation Notes?
These AHSEC Class 11 Physics Chapter 7 Gravitation Notes are made by subject experts of Assam Eduverse.
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