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Accuracy, Precision, and Significant Figures: quick check · Physics Playground

Exercises Units and measurement

Quick check from College Physics, 1.3 Accuracy, Precision, and Significant Figures

Accuracy, Precision, and Significant Figures: quick check

Perform the following calculations and express your answer using the correct number of significant digits.

(a) A woman has two bags weighing 13.5 pounds and one bag with a weight of 10.2 pounds. What is the total weight of the bags?

(b) The force $F$ on an object is equal to its mass $m$ multiplied by its acceleration $a$ . If a wagon with mass 55 kg accelerates at a rate of $0.0255 {m/s}^{2}$ , what is the force on the wagon? (The unit of force is called the newton, and it is expressed with the symbol N.)

Answer it in your own words before you look.

Answer
(a) 37.2 pounds; Because the number of bags is an exact value, it is not considered in the significant figures.
(b) 1.4 N; Because the value 55 kg has only two significant figures, the final value must also contain two significant figures.

How did it go?

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From College Physics (1st edition) by OpenStax (Rice University), section 1.3, licensed under CC BY 4.0. Original at openstax.org. We split the solution into steps; the words, numbers and figures are the book's. OpenStax doesn't endorse this site.