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WEEK 2 MEASUREMENTS AND UNITS

WEEK 2 MEASUREMENTS AND UNITS. Much of physics deals with measurement of physical quantities. Measurement is the process of finding the largeness or smallness of substance. It has to be followed by a unit called INTERNATIONAL SYSTEM OF UNITS (S.I).

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WEEK 2 MEASUREMENTS AND UNITS

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  1. WEEK 2MEASUREMENTS AND UNITS • Much of physics deals with measurement of physical quantities. Measurement is the process of finding the largeness or smallness of substance. It has to be followed by a unit called INTERNATIONAL SYSTEM OF UNITS (S.I). • Most of the physical quantities are related to length, time and mass. • Length is the extent of space or distance extended.

  2. Mass is the quantity of matter or material in a substance. • Time is that which events are distinguishable with reference to before or after • These basic quantities (LMT) are called fundamental quantities. The units are known as fundamental units(mks)

  3. FUNDAMENTAL QUANTITIES AND UNITS • Fundamental quantities are the basic quantities that are independent of others and cannot be defined in terms of other quantities or derived from them. • Fundamental units are the basic units upon which other units depend. They are the units of the fundamental quantities

  4. DERIVED QUANTITIES AND UNITS • These are obtained by some simple combination of the fundamental quantities and units e.g area-meters square, velocity-meters per second, force- kilogram meters per second square, etc.

  5. DIMENSIONS ANALYSIS • The dimensions of a physical quantity is the expression that specifies the power with which each of the fundamental quantities : Length-L, Time-T and Mass-M appear in a unit of a quantity The dimensions of a quantity is determined as follows: • Speed(velocity) = distance/ time = L/T = LT-1 • Acceleration = speed/time = L/T2 = LT-2 • Force = mass x acceleration = ML/T2 = MLT-2

  6. USES OF DIMENSION ANALYSIS • It supplies information about the measuring process of a physical quantity. • To check the correctness of equations. • It enables us to predict how physical quantities are related especially when the mathematics is too difficult.

  7. ASSIGNMENT 2 • State the limitations of dimension analysis. • What is the dimension for the following quantities : a) pressure b) absorbed dose c) electromotive force (e.m.f)

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