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• 1-2 Measuring Things

• February 16, 2022

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• Physics and engineering are based on the precise measurement of physical quantities (mass, time, length, pressure, etc.).
• We measure each quantity by its own “unit” or by comparison with a standard.
• A unit is a measure of a quantity that scientists around the world can refer to.
• A standard . This has to be both accessible and invariable.
• For example; 1 meter (m) is a unit of length. Any other length can be expressed in terms of 1 meter.
• A variable length, such as the length of a person’s nose is not appropriate.
• Base quantities:
• Seven fundamental quantities.
• Three are needed for mechanics: length, time, mass.
• All have been assigned standards.
• Are used to define all other physical quantities.

• PHY101 Physics I © Dr.Cem Özdoğan