## 2.1 DEFINITIONS AND BASIC UNITS OF MECHANICS

In this section we will deal with two measurement systems: the U.S. customary gravitational system, and the SI absolute system, which uses metric units. Some commonly measured mechanical properties are defined here.

Acceleration
Time rate of change of velocity. It is thus a time rate of change of a time rate of change.
Components
The single individual forces that are the equivalent of the resultant.
Concurrent
Forces whose lines of action or directions pass through a common point, or meet at a common point.
Coplanar
Forces all in the same plane.
Couple
A system of nonconcurrent forces tending to produce rotation about an axis.
Dynamics
Concerns bodies not in equilibrium; i.e., not at rest or with nonuniform motion.
Inertia
A property of matter that causes it to resist change in its motion or its state of rest.
Kinematics
A branch of dynamics that deals only with motions of bodies, not considering forces. It can thus be described as the geometry of motion.
Kinetics
A branch of dynamics that relates the actions of forces to the resulting motions of bodies.
Mass
The measure of the inertia of a body. Mass also initiates gravitational attraction.
Mechanics
The science that deals with forces and their effects on bodies at rest or in motion.
Moment
A force with respect to a point, which is the product of the force and the perpendicular distance from the point to the direction of the force (line of force). The distance...

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Accelerometers
Accelerometers are instruments for measuring, displaying, and analyzing acceleration and vibration.
Cyclone Separators
Cyclone separators and centrifugal separators utilize centrifugal, gravitational, and inertial forces to remove fine particles suspended in air or gas.
Control Valves
Control valves or proportional valves are power-operated devices used to modify fluid flow or pressure rate in a process system.
Scales and Balances
Scales and balances are used to measure static or dynamic loads for a wide range of industrial applications.
Motion Reference Units (MRU)
Motion reference Units (MRU) is a solid state motion reference device capable of measuring pitch, roll, heave, and heading to a high degree of accuracy

##### Topics of Interest

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