1-1 Standards of Length, Mass, and Time (mks units)
The laws of physics are expressed as mathematical relationships among physical quantities that we will introduce and discuss throughout the lectures. In mechanics, the three basic quantities are length, mass, and time. All other quantities in mechanics can be expressed in terms of these three.
In 1960, an international committee established a set of standards for the fundamental quantities of science. Three fundamental quantities which are subject to measurement:
1. Intervals in space: i.e., lengths.
2. Quantities of inertia, or mass.
3. Intervals in time.
Each of the three fundamental quantities. length, mass, and time, is measured with respect to some convenient standard. The system of units currently used by all scientists, is called the mks system, after the first initials of the names of the units of length, mass, and time, respectively, in this system: i.e., the meter, the kilogram, and the second. Sometime, its is called the SI (System International). Other SI standards established by the committee are those for temperature (the Kelvin), electric current (the ampere), luminous intensity (the candela), and the amount of substance (the mole).
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .