How to choose a spring: Basics?

Machine Design says: Spring are mechanical devices that store and apply kinetic energy. They’ve been around a long time and continue to play essential roles in a wide range of machines, vehicles, and engineering tools. But with so many different types of springs to choose from, it is important engineers understand what an application will require a spring to do before selecting the best one for that application. They also need to consider how springs will interact with other components. 

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