Question

Un cub cu latura l=10 cm si densitatea 2,7 g/cm cub este agatat de un dinamometru.
a) Cunoscand g=10N/kg determinati forta deformatoare
b)Cunoscand constanta elastica a resortului dinamometru, k=100N/m determinatialungirea acestuia

Answer 1

[tex]\displaystyle Se~da:\\ \\ l=10cm=0,1m\\ \\ \rho=2,7\frac{g}{cm^3}=2700\frac{kg}{m^3}\\ \\ a)g=10\frac N{kg},~F_{el}=?N\\ \\ b)k=100\frac{N}{m},~\Delta l=?m\\ \\ \\ Formule:\\ \\ a)F_{el}=G\\ \\ \\ G=m\times g\\ \\ \\ m=V\times\rho\\ \\ \\ V=l^3\Rightarrow m=l^3\times\rho\Rightarrow G=l^3\times \rho\times g\Rightarrow F_{el}=l^3\times \rho\times g[/tex]


[tex]\displaystyle b)F_{el}=k\times \Delta l\Rightarrow \Delta l=\frac{F_{el}}{k}\\ \\ \\ Calcule:\\ \\ a)F_{el}=0,1^3\times 2700\times 10=27N\\ \\ b)\Delta l=\frac{27}{100}=0,27m[/tex]