Final answer:
The biggest concern with the bag's weight is the percent uncertainty, which would increase if the bag's weight were reduced while the absolute uncertainty remained unchanged. To calculate the new percent, divide the constant uncertainty by the new weight and multiply by 100%. This concept is significant for scientific precision but takes on different emotional weight in personal contexts such as the tragedy following the Sichuan earthquake.
Step-by-step explanation:
The biggest worry associated with the bag seems to be the percent uncertainty in the weight measurement of the apple bag. If we have a bag that weighs 5 pounds with an uncertainty of ± 8%, this means that the actual weight could be 8% less or more than the stated 5 pounds. In case the bag of apples weighs half as much, or 2.5 pounds, but the uncertainty in weight remains the same, the percent uncertainty would change because it is relative to the total weight.
For calculations, the uncertainty in pounds would stay at the same value, but since it's now a larger fraction of the total weight, the percent uncertainty would effectively double. To calculate the new percent uncertainty, you would divide the uncertainty in pounds by the new weight (2.5 pounds) and then multiply by 100% to convert the decimal into a percentage. Keeping the same absolute uncertainty while reducing the weight of the bag increases the percent uncertainty.
In a real-world context, the weight of a bag might not have such a significant impact, but these calculations matter greatly in scientific measurements where precision is critical. As for the personal anecdote of using backpacks after the Sichuan earthquake, the biggest worry may be the symbolism of the bags and how they recall the tragic loss of life and the issue of lessened individual visibility in the face of state narratives.