Problema esentiala, chiar mai usoara decit celelalte, insa necesita cunoasterea formulei pentru modului lui Young.
[tex]Se~da:\\ \\
m=2t=2000kg\\ \\
v=1,5\frac ms\\ \\
\alpha=30^\circ\\ \\
S=1cm^2=10^{-4}m^2\\ \\
d=10m\\ \\
E=2\times10^{11}\frac{N}{m^2}\\ \\
\mu=0,1\\ \\
g=10\frac m{s^2}\\ \\
a)F=?N\\ \\
b)P=?W\\ \\
c)\Delta x=?m\\ \\ \\[/tex]
[tex]Formule:\\ \\
a)F=G_x+F_{fr}\\ \\
F=G\times \sin\alpha+\mu\times N\\ \\
F=G\times\sin\alpha+\mu\times G_y\\ \\
F=G\times\sin\alpha+\mu\times g\times\cos\alpha\\ \\
F=m\times g\times(\sin\alpha+\mu\times\cos\alpha)\\ \\ \\
b)P=F\times v\\ \\ \\
c)E=\frac{F\times d}{\Delta x\times S}\\ \\
\Delta x=\frac{F\times d}{E\times S}\\ \\ \\
[/tex]
[tex]Calcule:\\ \\
F=2000\times 10\times(\sin30+0,1\times\cos30)\approx 11732N\\ \\
P=11732\times 1,5\approx 17600W\\ \\
\Delta x=\frac{11732\times 10}{2\times10^{11}\times 10^{-4}}\approx 0,0059m[/tex]
