A spring of length 0.1m obeys hookes law when a load of 200N is hung vertically from its free end,the length of the spring become 0.115m.find? (a) calculate its new length when a load of 600N is hung on the spring. (b) name a device whose functioning depends on hookes law.

Answer 1

600 = 3*200
so, it will extend 3*0.015 = 0.045m

anything involving springs, like a spring scale
google can provide you with many more. In fact, I'd bet your text presents several examples.