[tex]m=2 \ kg \\ k=400 \ N/m \\ \boxed{\Delta l-?} \\ \bold{Rezolvare:} \\ \boxed{k=\frac{F_e}{\Delta l}} \Rightarrow \Delta l= \frac{F_e}{k}\\ F_e=G=m \cdot g \\ g=10 \ N/kg \\ F_e=G=2 \ kg \cdot 10 \ N/kg=20 \ N \\ \Delta l= \frac{20 \ N}{400 \ N/m} \\ \Rightarrow \boxed{\Delta l =0,05 \ m= \boxed{5 \ cm}}[/tex]
