Physics and Measurement Cheatsheet

Key Concepts

• Units of Measurement: Standard quantities used to express physical properties, e.g., meter (m) for length, kilogram (kg) for mass.
• System of Units: A set of units used consistently, e.g., CGS (centimeter-gram-second) and MKS (meter-kilogram-second).
• SI Units: International System of Units with seven base units, including meter (m), kilogram (kg), second (s).
• Fundamental Units: Base units independent of others, e.g., length, mass, time.
• Derived Units: Units derived from fundamental units, e.g., velocity (\( \frac{m}{s} \)), force (\( N = kg \cdot \frac{m}{s^2} \)).
• Least Count: Smallest division measurable by an instrument, e.g., 0.1 cm for a ruler.
• Significant Figures: Digits in a number that contribute to its precision, e.g., 5.03 has three significant figures.
• Errors in Measurement: Types include systematic (consistent bias) and random (unpredictable) errors.
• Dimensions: Express physical quantities in terms of fundamental units, e.g., velocity is \( [L T^{-1}] \).
• Dimensional Analysis: Technique to check equations or derive relationships using dimensions.

Quick Reference Table

Advice

Physics and Measurement Quick Tips

• SI Units: Always use SI units unless specified otherwise for consistency.
• Significant Figures: In calculations, maintain the least number of significant figures from inputs.
• Least Count: Check the instrument’s least count before measuring to ensure precision.
• Error Reduction: Minimize systematic errors by calibrating instruments.
• Dimensional Analysis: Use to derive formulas or check correctness of physical equations.