[tex]\displaystyle\\
\text{Energia potentiala inmagazinata in resort este: }\\\\
E_p = \frac{kx^2}{2}
\text{unde" }\\
E_p=14,4~J = \text{energia potentiala inmagazinata in resort.}\\
k = 20~ \frac{N}{m}= \text{constanta elastica a resortului.} \\
x = ? \text{ arata cu cat trebuie alungit resortul.} \\\\
\text{Rezolvare: }\\\\
E_p = \frac{kx^2}{2}\\\\
14,4 = \frac{20x^2}{2}\\\\
14,4 = 10x^2~~~\Big|: 10\\\\
1,44 = x^2\\\\
x^2 = 1,44\\\\
x= \sqrt{1,44}\\\\
\boxed{\bf x = 1,2~m }
[/tex]
