What you will learn in Rotational Motion & Gravitation

1. 1. Torque & Rotational Equilibrium

   Torque is force's rotational analogue — it depends on lever arm as much as magnitude.

2. 2. Moment of Inertia

   Mass distribution, not just total mass, determines how hard a shape is to spin.

3. 3. Rotational Kinetic Energy & Rolling Motion

   A rolling object splits its energy between moving forward and spinning — the split decides who wins the race.

4. 4. Angular Momentum & Its Conservation

   Angular momentum stays constant in an isolated system — spin rate and moment of inertia trade off to keep it that way.

5. 5. Newton's Law of Universal Gravitation

   Every mass pulls on every other mass — the same inverse-square law at every scale, from tabletop objects to planets.

6. 6. Gravitational Field Strength

   A field describes force-per-unit-mass at every point in space, independent of any particular second mass.

7. 7. Orbital Mechanics

   An orbit is nothing more than circular motion where gravity happens to supply the centripetal force.

8. 8. Kepler's Laws

   Kepler found these rules empirically; Newton's gravitation derives both of them from first principles.

9. 9. Centre of Mass & Its Motion

   A whole system of particles moves, as far as external forces are concerned, like one particle at its centre of mass.