Question

Un fir de cauciuc de lungime 1 metru si sectiune 10mm² se alungeste cu 1 cm.Ce marime are forta de deformare ?
(E=9,8 ·10⁴ N/m²)
Multumesc !

Answer 1

[tex]Avem\ ca:\\ L=1\ m\\ S=10\ mm^2=10^{-5}\ m^2\\ \Delta l=1\ cm=10^{-2}\ m\\ E=9,8\cdot 10^4 \frac{N}{m^2}\\ Aplicand\ legea\ lui\ Hook:\\ \frac{F}{S}=E\cdot \frac{\Delta l}{L}\\ F=\frac{S\cdot E\cdot \Delta l}{L}\\ F=\frac{10^{-5} \cdot9,8\cdot 10^4 \cdot10^{-2}}{1}\\ F=9,8\cdot 10^{-3} N [/tex]