Physics Units and Dimensions

Units and Measurements : Units and Measurements The international System of Units . Ways of measurement . Accuracy of data. Errors in measurements. Use of measurements and their applications .

The International system of Units : The International system of Units Physics deals with calculations and the numbers have a significance with respect to the real world .For example You can count the apples in a basket , the same apples can be weighed also and then they would be described by the weight they have . Now Suppose if we didn’t had any Units both quantities would represent a number however that would just lead to confusion since a third person won’t know that the number you are talking about is weight or count of the apple. It was clear that we needed to describe our quantities but this just got us into another problem. For example let’s say we go to a foreign country and we buy stuff there and when its time to pay we give our home currency this won’t work Unless the merchant knew how to do conversion from our home currency to his home currency . In order to avoid chaos The units and quantities were Standardized so that anyone could do the conversion to another Unit if required this led to the SI system of Units and quantities. Basic Units and Quantities Base Units and Quantities are those which are the lowest or in other words simple. These Units are also termed as fundamental since they can’t be derived from any other Unit

Ways of Measurement : Ways of Measurement There are basically three Units that are fundamental . Every other Unit is formed by a combination of these three Units. Mostly New names have been given to those Units which are used widely in physics and Some have been given new names Since The combination of the fundamental Units was too cumbersome to write. The three basic fundamental Units are Length Mass Time All other Units can be derived from these three fundamental Units

Measurement of Length : Measurement of Length The Unit of length is used to measure the distance in physics. Depending upon how Small or large the distance is different techniques are used to calculate the distances . The measurement techniques an described below For slow moving objects for example planets the length is measured in terms of angle Swept during a particular period of time that angle is called as Parallex angle.

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