DEGREE OF FREEDOM

An unconstrained rigid body in space can describe the following independent motions:

1. Translational motion along any three mutually perpendicular axes (x, y, or z)
2. Rotational motion about these axes

• A rigid body possess 6 degree of freedom
• for a body, number of restraints can never be-
• six (joint becomes solid)
• zero (joint is disconnected)

Degree of freedom of a pair is defined as the number of independent relative motion, both translational and rotational.

Degree of freedom of a pair = 6 - number of restraints