High School

Suppose that your bathroom scale reads your mass as 67 kg with a 3.0% uncertainty. What is the uncertainty in your mass? Use 2 significant digits.

A. 2.0 kg
B. 2.0 g
C. 2.0%
D. 0.02 kg

Answer :

Final answer:

The uncertainty in mass with a 3% uncertainty for a scale reading of 65 kg is calculated by multiplying the mass by the percentage uncertainty, which results in 1.95 kg and then is rounded to 2.0 kg when using two significant digits.

Explanation:

The question asks about the calculation of uncertainty in a measurement of mass with a given percentage of uncertainty. If a bathroom scale reads your mass as 65 kg with a 3% uncertainty, the uncertainty in kilograms can be found by multiplying the mass by the percentage uncertainty.

To calculate it:

  • (Mass in kg) × (Percentage uncertainty) = Uncertainty in kg
  • 65 kg × 0.03 = 1.95 kg

Since we are asked to use two significant digits for the uncertainty, we round 1.95 kg to 2.0 kg. This means the correct answer to the question is: a. 2.0 kg.