Question

Add (9.8×103s)+(9.9×104s)+(0.0080×106s).Your answer should be expressed using the appropriate number of significant figures.

Answer 1

Answer on Question#38520 – Physics - Other

Add $(9.8 \times 10^{3} \mathrm{~s}) + (9.9 \times 10^{4} \mathrm{~s}) + (0.0080 \times 10^{6} \mathrm{~s}) =$

$$\begin{array}{l} (9.8 \times 10^{3} \mathrm{~s}) + (9.9 \times 10^{4} \mathrm{~s}) + (0.80 \times 10^{4} \mathrm{~s}) = \\ (0.98 \times 10^{4} \mathrm{~s}) + (9.9 \times 10^{4} \mathrm{~s}) + (0.80 \times 10^{4} \mathrm{~s}) = \\ (0.98 + 9.9 + 0.80) \times 10^{4} \mathrm{~s} = 11.68 \times 10^{4} \mathrm{~s} \end{array}$$

The answer is $11.68 \times 10^{4}$ is because it must have the same number of decimal places as the one with the least number of decimal places (rule of significant figures in addition and subtraction). In this case, 9.9 and has 1 decimal places while 0.80 has 2 decimal places. Thus, their difference must be expressed in 2 decimal places, which is $11.68 \times 10^{4}$ s

Answer: $11.68 \times 10^{4} \mathrm{~s}$