page_title: D'Alembert's principle
hierarchical_section_title: D'Alembert's principle
caption_attribution_description: Français&#160;: Portrait de Jean Le Rond d'Alembert (1717-1783)
context_page_description: D'Alembert's principle, also known as the Lagrange–d'Alembert principle, is a statement of the fundamental classical laws of motion. It is named after its discoverer, the French physicist and mathematician Jean le Rond d'Alembert. It is the dynamic analogue to the principle of virtual work for applied forces in a static system and in fact is more general than Hamilton's principle, avoiding restriction to holonomic systems. A holonomic constraint depends only on the coordinates and time. It does not depend on the velocities. If the negative terms in accelerations are recognized as inertial forces, the statement of d'Alembert's principle becomes The total virtual work of the impressed forces plus the inertial forces vanishes for reversible displacements. The principle does not apply for irreversible displacements, such as sliding friction, and more general specification of the irreversibility is required.
context_section_description: D'Alembert's principle, also known as the Lagrange–d'Alembert principle, is a statement of the fundamental classical laws of motion. It is named after its discoverer, the French physicist and mathematician Jean le Rond d'Alembert.  It is the dynamic analogue to the principle of virtual work for applied forces in a static system and in fact is  more general than Hamilton's principle, avoiding restriction to holonomic systems. A holonomic constraint depends only on the coordinates and time. It does not depend on the velocities. If the negative terms in accelerations are recognized as inertial forces, the statement of d'Alembert's principle becomes The total virtual work of the impressed forces plus the inertial forces vanishes for reversible displacements.  The principle does not apply for irreversible displacements, such as sliding friction, and more general specification of the irreversibility is required.
caption: Jean d'Alembert (1717–1783)
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