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Physics For Engineers2D

Measurement and Vectors - Theory & Concepts - Significant Figures

Fundamental principles of measurements, SI units, dimensional analysis, and vector algebra in physics for engineers.

Open the complete lesson
Interactive engineering simulation

Significant Figures & Measurement Lab

Learn the fundamental rules of significant digits. Compare real vs. measured values in the Lab, or parse complex arithmetic in the Sig-Fig Engine.

Interactive Expressions
Significant Figure Guidelines
  • Non-zero digits are always significant (4.74.7 has 22 sig figs).
  • Captive zeros between non-zeros are significant (503503 has 33 sig figs).
  • Leading zeros are never significant (0.020.02 has 11 sig fig).
  • Trailing zeros are significant only if a decimal point is explicitly shown (15.015.0 has 33 sig figs; 150150 is ambiguous).
Step-By-Step Parse Logic
Operand A (14.50):

Decimal present. Non-zero digits and trailing zeros are significant. Zeros before the first non-zero digit () are leading zeros and not significant. Total significant figures: 4. Decimal places: 2.

Operand B (3.2):

Decimal present. Non-zero digits and trailing zeros are significant. Zeros before the first non-zero digit () are leading zeros and not significant. Total significant figures: 2. Decimal places: 1.

Multiplication/Division Rule: Round to the least number of significant figures.

Operand A has 4 sig figs. Operand B has 2 sig figs. The least is 2 sig figs. Rounding the raw result (46.4) to 2 sig figs yields: 46.

Operand A Sig Figs
4
Operand B Sig Figs
2
Least Sig Figs
2
Raw Mathematical Output
46.4
Significant Figure Rounded
46
Model scope and verification

Use the displayed units and idealizations, then verify the governing balance or compatibility equation before interpreting the result.