Question

un cub din lemn aref=0,95g/cm3si latura l=5cm.Agatand cubul de un resort acesta se alungeste cudl=23,7cm.Considerandg=10N/kgcare este valoarea

Answer 1

$\rho=0,95 \ g/cm^3 \\ a=5 \ cm \\ \Delta l=23,7 \ cm=0,237 \ m \\ \vec{g}=10 \ N/kg \\ k=\frac{F_e}{\Delta l} \\ \vec{F_e}=\vec{G}=m\vec{g} \\ \rho=\frac{m}{V} \ \Rightarrow m=\rho V \\ V=a^3=(5 \ cm)^3=125 \ cm^3; \\ \Rightarrow m=0,95 \ g/cm^3 \cdot 125 \ cm^3=118,75 \ g=0,11875 \ kg \\ \Rightarrow \vec{F_e}=0,11875 \ kg \cdot 10 \ N/kg=1,1875 \ N; \\ \Rightarrow k=\frac{1,1875 \ N}{0,237 \ m} \\ \Rightarrow \boxed{k=5 \ N/m}$