Question

Ce distanta trebuie sa parcurga in corp aflat initial in reapus sub actiunea unei forte de 8N, daca puterea medie dezvolta de ea cinstituie 60W , iar acceleratia miscarii cropului este egala cu 4m/s²?

Answer 1

[tex]\displaystyle Se~da:\\ \\ F=8N\\ \\ P=60W\\ \\ a=4\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~incepe~din~repaus,~deci~v_0=0)\\ \\ d=\frac{v^2}{2\times a}\\ \\ \\[/tex]


[tex]\displaystyle P=F\times v\Rightarrow v=\frac{P}{F}\\ \\ \\ d=\frac{P^2}{2\times a\times F^2}\\ \\ \\ Calcule:\\ \\ d=\frac{60^2}{2\times 4\times 8^2}=7,03125m[/tex]