1. Balance and the Pas de Deux
Alejandro Garcia

2. Pas de Deux
Translated literally from the French, pas de deux means “step of two.”
In ballet this term refers to a dance of two persons, typically a man and a woman dancing as partners.
Photo from Physics and the Art of Dance by K. Laws

3. Forces on the Ballerina
Forces acting on the ballerina are:
Gravity
Support (floor)
Friction (floor)
Friction (hands)
Friction
(CG) X
Gravity
Support
(Floor)
Friction
Without her partner, the ballerina would fall forward.

4. Dancers as a Single Object
Taken as a single object, the dancers’ center of gravity is located, roughly, as shown.
The upward vertical support force of the floor balances the gravity force (their total weight) X
(CG)
Gravity
Support
(Floor)
Support
(Floor)
Support
(Floor)

5. Base of Support
The pose is stable as long as the center of gravity is located above the base of support, the area outlined below.

6. References
For more information on balance and the physics of the pas de deux:
Physics and the Art of Dance: Understanding Movement, Kenneth Laws, Oxford University Press (2002) Chapter 6, The Pas de Deux
Conceptual Physics , Paul G. Hewitt, Addison Wesley (2005) Chapter 10, Rotational Motion