📖 Dance Physics Rosetta Stone

A living appendix translating physics equations into plain English and dance insights.


Table of Contents

  1. Kinetic Energy
  2. Rotational Energy
  3. Potential Energy (Rise & Fall)
  4. Force
  5. Momentum
  6. Torque
  7. Lagrangian Mechanics
  8. Rayleigh Dissipation

Kinetic Energy

Equation:

\[ T = \tfrac{1}{2} m v^2\]

Plain English:
The energy of motion depends on how heavy something is and how fast it’s going.

Dance Analogy:
Your “oomph” traveling across the floor. A heavier dancer moving quickly has more drive — and more stopping difficulty.


Rotational Energy

Equation:

\[ T = \tfrac{1}{2} I \omega^2\]

Plain English:
The energy stored in turning depends on rotational inertia and spin speed.

Dance Analogy:
The “engine” of pivots and spins. Think of Viennese Waltz: the faster the turn, the more energy you’re managing.


Potential Energy (Rise & Fall)

Equation:

\[ V = \tfrac{1}{2} k (z - z_0)^2\]

Plain English:
Energy stored like a spring when displaced from equilibrium.

Dance Analogy:
Rise & Fall. When you rise above natural level, you’re “charging” energy that releases back into the lowering.


Force

Equation:

\[ F = m a\]

Plain English:
Force equals mass times acceleration.

Dance Analogy:
How much push the Leader needs to start motion. A heavier partner requires more force to accelerate.


Momentum

Equation:

\[ p = m v\]

Plain English:
Momentum is mass in motion — once moving, it resists stopping or changing direction.

Dance Analogy:
Quickstep or Foxtrot glide: momentum carries you forward smoothly, but also makes sudden halts harder.


Torque

Equation:

\[ \tau = r \times F\]

Plain English:
Rotational force depends on how far from the pivot the push is applied.

Dance Analogy:
Leading from the hand: a small input at the arm creates big rotation through the frame.


Lagrangian Mechanics

Equation:

\[ L = T - V\]

Plain English:
The balance between motion energy (T) and stored energy (V).

Dance Analogy:
The principle of “Least Action” in dancing: smooth movement happens when motion balances stored rise/fall energy.


Rayleigh Dissipation

Equation:

\[ \mathcal{D} = \tfrac{1}{2} c \dot{q}^2\]

Plain English:
Energy lost due to friction, drag, or damping.

Dance Analogy:
The hidden costs: shoe friction, floor resistance, or muscle fatigue. Why nothing is perfectly efficient.



Notes

  • Social dancers: skim the plain English.
  • Serious dancers: peek into the dance analogies.
  • Competitors: study the equations for performance edges.