“How do engineers specify the accuracy of their measurements?”
One of the most unfortunate aspects of the real world is that there will always be inefficiency, weather it be with the amount of energy available in a system or the weight distribution. One of the inefficiencies include the physical dimensions of an object. Specifically, material parts have small fluctuations in their sizes as a result of the manufacturing process so parts that should measure 5.1 meters in length can come out to be 5.143 or 5.102 meters. For a mass-produced machine, this could be an opprobrium, as the differences in physical size could lead to malfunctioning, which would causally prove disastrous. Luckily, engineers tend to be a very clever people, and they have invented something called engineering tolerancing to solve this issue. When giving off designs to a machinist, engineers will use significant figures to specify the tolerance that part can have. To illustrate a machine such as a cheap toy would not require a high precision, while something like a jet engine will!