Question

Poate cineva sa-mi rezolve problema atasata prezentand toti pasii?

Multumesc!

Answer 1

Forta de frecare produce o deceleratie de modul :

a=-Ff/m=-mgy/m=-gy

Viteza finala a corpului va fi 0.

Aplicam ecuatia lui Galilei:

v^2=v0^2+2ad
0=v0^2-2gyd
2gyd=v0^2
d=v0^2/2gy=100/4=25m

Answer 2

[tex]\displaystyle Se~da:\\ \\ v_0=10\frac ms\\ \\ \mu=0,2\\ \\ g=10\frac m{s^2}\\ \\ d=?m\\ \\ \\ Formule:\\ \\ d=\frac{\Delta v^2}{2\times a}\\ \\ d=\frac{v^2-v_0^2}{2\times a}~(Corpul~se~opreste,~deci~v=0)\\ \\ d=\frac{-v_0^2}{2\times a}\\ \\ \\[/tex]


[tex]\displaystyle Pe~axa~O_y:\\ \\ \overrightarrow{N}+\overrightarrow{G}=0\\ \\ N=G\\ \\ N=m\times g\\ \\ \\ Pe~axa~O_x:\\ \\ \overrightarrow{F}=m\times a\\ \\ -F_{fr}=m\times a\\ \\ -\mu\times N=m\times a\\ \\ -\mu\times m\times g=m\times a\\ \\ a=-\mu\times g\\ \\ \\[/tex]


[tex]\displaystyle d=\frac{-v_0^2}{-2\times \mu\times g}\\ \\ d=\frac{v_0^2}{2\times \mu\times g}\\ \\ \\ Calcule:\\ \\ d=\frac{10^2}{2\times 0,2\times 10}=25m[/tex]