Question

De un resort se atarna un paralelipipet care are : L =25 cm,l =15 cm,h =10 cm , S=8600 k\ m3 , K =300n /m. Care va fi alungirea resortului ?

S = densitetea

Answer 1

$L=25 \ cm=0,25 \ m \\ l=15 \ cm=0,15 \ m \\ h=10 \ cm=0,1 \ m \\ \rho=8600 \ kg/m^3 \\ k=300 \ N/m \\ \boxed{\triangle l-?} \\ \bold{Rezolvare:} \\ \boxed{k= \frac{F_e}{k} } \\ \boxed{F_e=G=m \cdot g} \\ \boxed{\rho= \frac{m}{V} } \\ \Rightarrow \triangle l= \frac{F_e}{k} \\ \Rightarrow m=\rho \cdot V \\ V=L \cdot l \ cdot h \\ V=0,25 \ m \cdot 0,15 \ m \cdot 0,1 \ m \\ V=0,00375 \ m^3 \\ \Rightarrow m=8600 \ kg/m^3 \cdot 0,00375 \ m^3 \\ m=32,25 \ kg \\ \Rightarrow F_e=G=32,25 \ kg \cdot 10 \ N/kg$
$\Rightarrow F_e=322,5 \ N \\ \Rightarrow \triangle l= \frac{322,5 \ N}{300 \ N/m} \\ \Rightarrow \boxed{\triangle l=1,075 \ m}.$