Question

O bucata de lemn de forma paralelipipedica are dimensiunile:L=30 cm,l=20 cm,h=10 cm si densitatea =800kg/m cub.Se agata de un resort cu constanta elastica K=400 N/m si lungimea initiala l zero=10cm.Ce lungime finala va avea resortul,dupa agatarea acestui corp?(g=10m/s la puterea 2)

Answer 1

[tex]V=L \cdot l \cdot h=0,3 \cdot 0,2 \cdot 0,1=0,006 \; m^3\\ \rho = \dfrac{m}{V} \Rightarrow m=\rho \cdot V=800 \cdot 0,006 = 4,8 kg\\ \vec{F_{el}} + \vec{G}=0\\ F_{el}-G=0 \Rightarrow F_{el}=G\\ k \cdot \Delta l= mg\\ \Delta l=\dfrac{mg}{k}= \dfrac{48}{400}=1,2m\Rightarrow l_{final}=l_{initial}+\Delta l=1,3m [/tex]