Kit Library / Science / Physics
⚡ Topic Learning KitShared by a Veda learner · Generated with Veda AI
Veda Bites are swipeable micro-lessons — each one teaches exactly one idea. The bites below come from this kit — swipe through them in the app.
💡 Key Idea
You attract the Earth — and it attracts you.
Gravitation is a universal attractive force between any two objects with mass. It is always attractive, never repulsive, and acts along the line joining their centres.
↳ Gravity is universal: every pair of masses in the universe attracts each other with this same law.
📖 Definition
One tiny number rules all of gravity.
↳ G is fixed everywhere; its tiny value is why gravity feels weak between everyday objects.
⚖️ Comparison
Your mass is constant; your weight is not.
↳ Mass is intrinsic; weight is the force gravity exerts on that mass at a given place.
➗ Formula
Weight is just mass times g.
↳ Weight = mass × local g; change location, and weight changes while mass does not.
⚙️ Process
Drop it — gravity does the rest.
Free fall is motion under gravity alone, with no air resistance or other forces. All objects in free fall accelerate at the same rate g, regardless of mass.
↳ In free fall, mass drops out — a feather and a hammer fall together in vacuum.
⚠️ Common Mistake
Bigger isn't faster in free fall.
↳ Mass does not affect free-fall acceleration; air resistance is the real culprit for everyday differences.
✏️ Example
No air, no excuses — they land together.
↳ Remove air resistance, and free fall becomes truly mass-independent.
➗ Formula
g is gravity's fingerprint on motion.
↳ g is a property of the planet, not the falling object.
🌍 Real World
They're falling — just missing Earth.
A satellite is in continuous free fall toward Earth, but its high horizontal speed makes it curve around Earth instead of hitting it. This balance of gravity and tangential velocity produces an orbit.
↳ Orbiting is free fall with enough sideways speed to keep missing the ground.
➗ Formula
The speed that keeps you circling.
↳ Orbital speed depends only on the central body's mass and the orbital radius.
➗ Formula
The speed to leave the planet for good.
↳ Escape velocity is the minimum speed to leave a planet's gravity permanently.
🧠 Memory Trick
Twice as far, one-fourth the pull.
Remember the inverse-square law: if distance doubles, gravitational force becomes 1/4; if distance triples, it becomes 1/9. Force ∝ 1/r².
↳ Distance squared in the denominator — double r, quarter F.
🎯 Exam Tip
r is centre-to-centre, not surface-to-surface.
↳ r is always centre-to-centre; add the planet's radius when given height.
❓ Did You Know
Weakest force, biggest cosmic job.
Gravity is by far the weakest of the four fundamental forces, yet it dominates on cosmic scales because it is always attractive and has infinite range — it never cancels out.
↳ Weak locally, dominant cosmically — gravity's always-attractive nature wins at scale.
🛠️ Application
From tides to GPS — gravity at work.
↳ Gravitation underpins tides, satellite tech, space travel, and everyday weighing.
Gravitation is the universal attractive force between any two masses, governed by Newton's inverse-square law. It explains why objects fall, why planets orbit, and how weight differs from mass. This kit covers the core l…
Full explanation, worked examples & memory tricks in the app
All 18 questions, laddered from warm-up to topper-level, each with its answer and the reasoning behind it.
Q1. Which statement best describes the nature of the gravitational force between two masses?
BeginnerAnswers and explanations are in the Veda app.
Q2. The gravitational force between two objects is $F$. If the distance between them is doubled, the new force is:
BeginnerAnswers and explanations are in the Veda app.
Q3. The SI unit of the universal gravitational constant $G$ is:
BeginnerAnswers and explanations are in the Veda app.
Q4. An astronaut in orbit feels weightless because:
BeginnerAnswers and explanations are in the Veda app.
Q5. A body has mass 10 kg on Earth. What is its mass on the Moon?
BeginnerAnswers and explanations are in the Veda app.
Q6. Which quantity is a force?
BeginnerAnswers and explanations are in the Veda app.
Q7. The value of $g$ at Earth's surface is approximately:
BeginnerAnswers and explanations are in the Veda app.
Q8. Newton's law of universal gravitation states $F = G m_1 m_2 / r^2$, with $G = 6.67 \times 10^{-11}\ \text{N m}^2/\text{kg}^2$.
BeginnerAnswers and explanations are in the Veda app.
Q9. A satellite is in a low circular orbit around Earth. Its orbital speed is about:
IntermediateAnswers and explanations are in the Veda app.
Q10. The gravitational force between two masses is $F$. If both masses are doubled and the distance is halved, the new force is:
IntermediateAnswers and explanations are in the Veda app.
Q11. Why does the Moon not crash into Earth?
IntermediateAnswers and explanations are in the Veda app.
Q12. A 1 kg book rests on a table. The gravitational force between Earth and the book is approximately:
IntermediateAnswers and explanations are in the Veda app.
Q13. A feather and a hammer are dropped on the Moon. What happens?
IntermediateAnswers and explanations are in the Veda app.
Q14. The gravitational force between two everyday objects is negligible mainly because:
AdvancedAnswers and explanations are in the Veda app.
Q15. A satellite is moved from Earth's surface to an altitude equal to Earth's radius. By what factor does the gravitational force on it change?
AdvancedAnswers and explanations are in the Veda app.
Q16. Which observation most directly supports the inverse-square law of gravitation?
AdvancedAnswers and explanations are in the Veda app.
Q17. A satellite is in a low circular orbit around Earth at an altitude of 400 km. Calculate the gravitational force acting on a 1000 kg satellite. Use the formula $$F = G \frac{m_1 m_2}{r^2}$$ where $m_1 = 6 \times 10^{24}\ \text{kg}$ (mass of Earth), $m_2 = 1000\ \text{kg}$ (mass of the satellite), and $r = R + h$ with $R = 6.4 \times 10^6\ \text{m}$ (radius of Earth) and $h = 400 \times 10^3\ \text{m}$ (altitude).
AdvancedAnswers and explanations are in the Veda app.
Q18. Using Kepler's third law, if a planet orbits a star at a distance of 2 AU (astronomical units), what is the ratio of its orbital period squared to the cube of its semi-major axis? Assume the star's mass is similar to that of the Sun. Express your answer in terms of the formula $$T^2 \propto a^3$$.
AdvancedAnswers and explanations are in the Veda app.
20 flashcards in this kit — the app reviews them with spaced repetition so the right card returns on the right day.
Every game is built from this kit's own content — scores feed your mastery, so playing counts as studying.
Word Match
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True False
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Memory Match
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Flashcard Battle
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Speed Quiz
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Guess Term
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Sequence Builder
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Categorization
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Revision Battle
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Playable in the app
The full Veda Bites deck, complete notes, spaced-repetition flashcards, leveled MCQs, tests and games for this kit — plus Daily Facts and the Arena, every day.