equilibrium
and 
for all time, where r is the position vector of the particle. We then say that r0 is an equilibrium or equilibrium position.
Consider a rigid body experiencing a system of forces. Let F be the total force and M the moment of the forces about the origin. The rigid body is in equilibrium when it is at rest and F = 0 and M = 0 for all time.
A body, in equilibrium, is in stable equilibrium if, following a small change in its position, it returns to, or remains close to, the equilibrium position. It is in unstable equilibrium if, following a small change in its position, it continues to move further from the equilibrium position. See linear theory of equilibria, Lyapunov stability.
- constant function
- constant of integration
- constant of proportionality
- constants
- constant speed
- constant term
- constrained optimization
- constraint
- constructible number
- construction with ruler and compass
- constructive
- constructivism
- contact
- contact force
- contained in
- content
- contingency table
- contingent
- continued fraction
- continuity correction
- continuity equation
- continuous data
- continuous function
- continuously differentiable
- continuous random variable