Learning objective
Apply gravitational force, field and potential ideas to simple systems.
CLASS 11 PHYSICS
Gravitation
Understand the universal attraction that governs planets and falling bodies.
State Board to NCERT bridge
From falling objects to the same force acting between all masses.
Tamil concept bridge
Gravity oru bhoomi mattum seyyum force alla; ella masses-kum idaiyil irukkum universal force.
GUIDED LESSON
Learn the chapter step by step
Read one concept, explain it in your own words, then connect it to the formula or situation that follows. Do not try to memorise the chapter as isolated definitions.
Every pair of masses attracts with F = Gm1m2/r2. The force is along the line joining the masses and follows an inverse-square law.
Tamil support: Gravity oru bhoomi mattum seyyum force alla; ella masses-kum idaiyil irukkum universal force.
Ask yourself: Can I give one everyday example of universal law of gravitation?
WORKED EXAMPLE
Inverse-square comparison
Given: The separation between two masses is doubled.
- 1Gravitational force is proportional to 1/r^2.
- 2Replace r by 2r.
- 3The factor becomes 1/(2^2).
Answer: The force becomes one-fourth of its original value.
FORMULA / FACT BANK
Know what each relationship means
Gravitational force
F = Gm1m2 / r^2
Attraction between two point masses.
Potential energy
U = -GMm / r
Taking zero at infinity.
Memory cue: inverse square law · g and G · escape speed · satellites
SELF-CHECK
Which concept should you start with?
Choose the core foundation concept for this chapter.
COMMON MISTAKES
- Do not use a formula before identifying the physical quantities and their SI units.
- Keep direction, sign convention and stated conditions visible throughout a solution.
- Check whether your answer has a sensible unit and magnitude.
REVISION PLAN
- 1. Re-read the visual summary and say each revision target aloud.
- 2. Redo the worked example without looking at the steps.
- 3. Complete the 80-question bank and revisit every incorrect explanation.
VISUAL NOTES
Gravitation at a glance
Universal gravitation
Relate attraction to masses and separation.
Acceleration due to gravity
Explain why g can vary with location.
Satellites
Connect orbital motion to gravitational force.
Formula / fact focus
Gravitational force
F = Gm1m2 / r^2
Potential energy
U = -GMm / r
Last-minute memory cues
- 1. ✓inverse square law
- 2. ✓g and G
- 3. ✓escape speed
- 4. ✓satellites
NEXT IN THIS CHAPTER
Practise this chapter with its complete 80-question MCQ bank, then use the video and revision notes to strengthen any weak areas.