Question

(a) A person’s blood pressure is measured to be 120±2mm Hg. What is its percent uncertainty? (b) Assuming the same percent uncertainty, what is the uncertainty in a blood pressure measurement of 80 mm Hg?

a) (a) 1.67% (b) ±1.33 mm Hg (c) ±1.67 mm Hg (d) ±2.67 mm Hg
b) (a) 1.67% (b) ±1.33 mm Hg (c) ±1.67 mm Hg (d) ±2.67 mm Hg

Answer 1

The percent uncertainty of the blood pressure measurement is 1.67%, and the uncertainty in a measurement of 80 mm Hg is ±1.336 mm Hg.

Step-by-step explanation:

To calculate the percent uncertainty, we divide the uncertainty by the measured value and then multiply by 100. For the blood pressure measurement of 120 ± 2 mm Hg:

Percent uncertainty = (2/120) × 100 = 1.67%

To find the uncertainty in a blood pressure measurement of 80 mm Hg, we use the same percent uncertainty:

Uncertainty = (1.67/100) × 80 = ±1.336 mm Hg