0], at rest in its local

inertial frame, has constant velocity [[?

O] from

inertial frame to the local frame x-y attached to the end-effector k; see Fig.

x] where [omega] represents the part of angular rate vector of the body frame with respect to the

inertial frame projected to the x axis of body frame).

For a world without gravity, he discusses non-relativity for relativists, the invariance of physical law under change of

inertial frame of reference, using and understanding the Lorentz transformation, the measure of space-time, and electromagnetic theory in space-time.

The remainder of this article is, will be, or has been, depending on the reader's

inertial frame, divided into three sections.

The joint orientation with respect to

inertial frame is defined by:

The ground plane is described in the

inertial frame {[f.

An accelerated coordinate system is not an

inertial frame.

In other words, if relative velocities are in average and magnitude close to the speed of light, the twin in the spaceship experiencing the most changes of

inertial frame (including taking off, turning around, and braking vs.

We will use as our reference frame F[x, y, z, t], the idealized laboratory

inertial frame, abbreviated to lab, to describe the location of particles and fields at time t We will use other reference systems like F'[x' ,y' ,z' ,t'] with axes parallel with respect to F, with the origins of these systems coinciding at t = t' = 0 and with F' being in uniform relative motion with respect to F in either the positive or negative x direction.