Gravity
Also known as: gravitational force, g
The universal attractive force between any two objects with mass, decreasing with the square of distance. Governs planetary motion, ocean tides, and keeps us on Earth's surface.
💡 Intuition
Everything pulls on everything else—but only huge things (like Earth) pull noticeably.
Core Idea
Gravity acts between all masses everywhere — it never turns off, only weakens with distance.
Formal View
🔬 Example
🎯 Why It Matters
Governs planetary motion, ocean tides, and keeps us on Earth's surface.
⚠️ Common Confusion
Gravity never 'turns off' in space—astronauts float because they're falling around Earth.
💭 Hint When Stuck
When you see a gravity problem, identify the two masses and the distance between their centres. First, substitute m_1, m_2, and r into F = Gm_1 m_2 / r^2. Then compute the numerator and denominator separately before dividing. Finally, check your answer's units are in newtons.
Related Concepts
How Gravity Connects to Other Ideas
To understand gravity, you should first be comfortable with force and mass. Once you have a solid grasp of gravity, you can move on to weight.
Compare With Similar Concepts
Common Mistakes Guides
Go Deeper
Frequently Asked Questions
What is Gravity in Physics?
The universal attractive force between any two objects with mass, decreasing with the square of distance.
Why is Gravity important?
Governs planetary motion, ocean tides, and keeps us on Earth's surface.
What do students usually get wrong about Gravity?
Gravity never 'turns off' in space—astronauts float because they're falling around Earth.
What should I learn before Gravity?
Before studying Gravity, you should understand: force, mass.
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