Final answer:
Safety net drop-tests require a 37.2-pound bag of sand, where the focus is placed on measurement accuracy underscored by the principle of significant figures.
Step-by-step explanation:
Safety net drop-tests must consist of a 37.2 pound bag of sand being dropped into the net. This specification ensures that the safety net can withstand a significant impact, which is a critical aspect of ensuring the safety of workers who may rely on the net in case of a fall. The significant figures principle is used in measuring the weight of the bag of sand, emphasizing the accuracy of the measurement. It is vital to note that exact values, like the number of bags, do not factor into the count of significant figures.