Conceptual Dynamics - Independent Learning

Rigid-Body Motion


How does a rigid body move?


A rigid body may move in pure translation, pure rotation or in general planar motion.


In pure translation a body may only .




In pure rotation a body may only .




In general planar motion a body may and .




A particle can only translate and is described by its position, velocity and acceleration. A rigid body, in addition to translating, may also rotate. A rigid body is described by both linear and angular position, linear and angular velocity, and linear and angular acceleration.


Compare and contrast the linear and angular versions of the following equations.


Rotational Equations Translational Equations
ω = dθ/dt v = ds/dt
α = dω/dt a = dv/dt
α dθ = ω dω a ds = v dv