Final answer:
The percent uncertainty in the weight of a 5 lb bag with an uncertainty of ± 0.4 lb is calculated using the formula: (uncertainty / measured value) × 100. Substituting the given values, the percent uncertainty is found to be 8%.
Step-by-step explanation:
To calculate the percent uncertainty of the weight of a 5 lb bag with an uncertainty of ± 0.4 lb, you first need to understand the concept of percent uncertainty. The percent uncertainty is found by dividing the uncertainty of the measurement by the measured value and then multiplying by 100 to get a percentage. In this case, the average weight A of the bag is 5 lb, and the uncertainty SA is 0.4 lb.
The equation for percent uncertainty is:
% uncertainty = (SA / A) × 100
Substituting the given values:
% uncertainty = (0.4 lb / 5 lb) × 100 = 8%
Therefore, the percent uncertainty in the weight of the bag is 8%.