Chapter 1: Physics and Measurement — Revision Sheet

1. 📌 Essentials

• SI units are the standard system for physical quantities: meter (m), kilogram (kg), second (s), kelvin (K), ampere (A candela (cd), mole (mol).
• The meter is defined by the distance light travels in vacuum during 1/299,792,458 seconds.
• The second is based on the radiation period of cesium-133 atoms (9,192,631,770 cycles).
• Dimensional analysis verifies the consistency of physical equations using dimensions [L], [M], [T].
• Conversion factors are used to switch between units; some are exact (e.g., 1 in = 2.54 cm).
• Order-of-magnitude estimates provide approximate results within a factor of 10.
• Significant figures indicate measurement precision; rules govern their use in calculations.
• Multiplication/division results are limited by the least number of significant figures.
• Addition/subtraction results are limited by the least decimal places.
• Models simplify complex systems for analysis, including geometric, particle, analysis, and structural models.

2. 🧩 Key Structures & Components