Ch 2 covers the International System of Units (SI), significant figures, errors in measurement, and dimensional analysis — essential tools for any physics calculation.
SI has 7 base units: metre (m), kilogram (kg), second (s), ampere (A), kelvin (K), mole (mol), candela (cd). Derived units: m/s, N (kg·m/s²), J (N·m). Significant figures: all certain digits + one uncertain digit. Rules: leading zeros don't count; trailing zeros after decimal point count.
Error = measured − true value. Absolute error: |Δa|. Relative error = Δa/a. Percentage error = (Δa/a) × 100%. In addition/subtraction: absolute errors add. In multiplication/division: relative errors add. Dimensional analysis: every correct equation must be dimensionally consistent ([LHS] = [RHS]). Can check correctness, derive relations, but cannot determine dimensionless constants.
Download: https://ncert.nic.in/textbook/pdf/keph102.pdf | Part I: https://ncert.nic.in/textbook/pdf/keph1ps.zip
No. Dimensional analysis can check if a formula is correct or derive power relationships, but it cannot determine pure numeric constants (like 2π), nor can it handle dimensionless quantities (angles) or functions with multiple variables of the same dimensions.
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