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Units and Measurements — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysicsUnits and Measurements3 Marks
Question
Why length, mass and time are chosen as base quantities in mechanics?
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Answer

Normally each physical quantity requires a unit or standard for its specification, so it appears that there must be as many units as there are physical quantities. However, it is not so. It has been found that if in mechanics we choose arbitrarily units of any three physical quantities we can express the units of all other physical quantities in mechanics in terms of these. So, length, mass and time are chosen as base quantities in mechanics because.
  1. Length, mass and time cannot be derived from one another, that is these quantities are independent.
  2. All other quantities in mechanics can be expressed in terms of length, mass and time.

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