Central Forces & Angular Momentum | The Effective Potential | Classical Mechanics 16

Lecture 16: Two bodies become one body of reduced mass · a central force never changes the angular momentum · the sideways motion becomes a centrifugal wall, the effective potential · one energy line decides circle, wander, escape, or spiral in Problems: Why circular orbits are stable only for forces weaker than the inverse cube · the planet that spirals in, infinitely many turns in a finite time · the pivot the Earth and the Moon share, and weighing Pluto and Charon with a clock · a thrown baseball is on an orbit too Chapters: 00:00 The Planet That Falls In 01:02 Welcome and the Plan 01:48 Two Bodies Become One, a Body of Reduced Mass 03:14 A Pair Circles Its Center of Mass, Near the Heavy Body 04:43 A Central Pull Spins the Mass Faster as It Comes In 05:44 Angular Momentum Is Fixed by Any Central Force 07:28 The Effective Potential, One Curve for the Orbit 08:59 One Energy Line Decides Circle, Wander, or Escape 10:25 A Circle Survives a Nudge Only if the Curve Has a Bowl 11:49 A Circle Sits Where the Slope Is Zero 12:51 Circular Orbits Are Stable Only for n Greater Than −3 14:04 Why Space Has Three Dimensions 15:22 The Reduced Mass Cancels, the Period Weighs the Total 16:38 The Period Weighs the Pair, the Center of Mass Splits It 17:58 To Reach the Sun, First Stop Orbiting It 19:05 Two Conserved Laws Decide the Nearest Point 21:04 Hitting the Sun Costs Twice as Much as Leaving It 21:41 Three Habits for Central Forces 22:47 Coming Up 23:09 Credits Lecture Slides (PDF): https://sinhafoundation.org/slides/me... Watch the full course:    • Classical Mechanics · All Lectures   Course guide: https://sinhafoundation.org/physics New here? Start with Lecture 1:    • Dimensional Analysis & Estimation | Think ...   A project of the Amit & Deepali Sinha Foundation. (c) Sinha Foundation. All Rights Reserved.