# Mechanical Vibration/Units

## Units

Before you begin the second chapter of this book be sure to refamiliarize yourself with the following physical measurements. In the typical fashion of working almost exclusively in SI units as part of an effort to remove the engineering profession from outdated unitary systems, this text will present all problems in SI. You should be familiar with their English equivalents; afterall, if you plan on working in the United States you will be using English Units. The table below should cover all the units we will use throughout the text.

Parameter SI
Mass
$\!\mathrm{kg}$
Angle
$\!\mathrm{rad}$
Acceleration
$\frac{\mathrm{m}}{\mathrm{s}^2}$
Length
$\!\mathrm{m}$
Force
$\!\mathrm{N}$
Spring constant
$\frac{\mathrm{N}}{\mathrm{m}}$
Torsional Spring constant
$\frac{\mathrm{N m}}{\mathrm{rad}}$
Damping constant
$\frac{\mathrm{N sec}}{\mathrm{m}}$
Mass moment of inertia
$\!\mathrm{kg m}^2$