Question

The speed of a bullet train is measured to be 312.0 mpg +/- 3.9 mph. What is the percent uncertainty in this measurement?(1 point) Responses 1.3 % 1.3 % .13 % .13 % 14.4% 14.4% .14 %

Answer 1

To calculate the percent uncertainty, you can use the following formula:

\[
\text{Percent Uncertainty} = \left(\frac{\text{Uncertainty}}{\text{Measured Value}}\right) \times 100\%
\]

In this case, the measured value is 312.0 mph and the uncertainty is 3.9 mph.

Substituting the values into the formula:

\[
\text{Percent Uncertainty} = \left(\frac{3.9}{312.0}\right) \times 100\%
\]

Calculating that gives:

\[
\text{Percent Uncertainty} = \left(0.0125\right) \times 100\% \approx 1.25\%
\]

Rounding to three significant figures, the percent uncertainty is approximately **1.3%**.

Thus, the correct response is **1.3%**.