Unit 6 Listen and Read:
Basic Terminologies in Mechanics
The following are the basic terms to study mechanics, which should be understood clearly: mass, time, space, length, displacement, velocity, acceleration, momentum, continuum, rigid body and particle. Length. It is a concept to measure linear distances. Mass. The quantity of the matter possessed by a body is called mass. The mass of a body will not change unless the body is damaged and part of it is physically separated. Time. Time is the measure of succession of events. The successive event selected is the rotation of earth about its own axis and this is called a day. Space. The geometric region in which study of body is involved is called space. Displacement. Displacement is defined as the distance moved by a body/particle in the specified direction, and others. Length (L), Mass (M) and Time (T) are the fundamental units in mechanics. The units of all other quantities may be expressed in terms of these basic units.