[tex]k=400 \ N/m \\ m=4 \ kg \\ g=10 \ N/kg \\ \boxed{\Delta l-?} \\ \bold{Rezolvare:} \\ \boxed{k= \frac{F_e}{\Delta l} \Rightarrow \boxed{\Delta l= \frac{F_e}{k} }} \\ F_e=G=m \cdot g \\ F_e=G=4 \ kg \cdot 10 \ N/kg \\ F_e=40 \ N \\ \Delta l= \frac{40 \ N}{400 \ N/m} \\ \Rightarrow \boxed{\Delta l= 0,1 \ m} [/tex]
