A computer will make this latter task much more
palatable. If we choose to use the graphical approach to analysis, we will have to do an
independent graphical solution for each of the positions of interest. None of the information
obtained graphically for the first position will be applicable to the second position
or to any others. In contrast, once the analytical solution is derived for a particular
automobile in the analysis. In that case a global coordinate system attached to the car
would be useful, and we could consider it to be an absolute coordinate system. Even if
we use the earth as an absolute reference frame, we must realize that it is not stationary
either, and as such is not very useful as a reference frame for a space probe. Though we
will speak of absolute positions, velocities, and accelerations, keep in mind that ultimately,
until we discover some stationary point in the universe, all motions are really relative.
The term inertial reference frame is used to denote a system which itself has no
acceleration. All angles in this text will be measured according to the right-hand rule.
That is, counterclockwise angles, angular velocities, and angular accelerations are positive
in sign.