Question

ajutatima va rog la 2 la 3 si la 5

Answer 1

[tex]2)Se~da:\\ \\ v_0=3\frac ms\\ \\ t=3s\\ \\ g=10\frac m{s^2}\\ \\ v=?\frac ms\\ \\ d=?m\\ \\ \\ Formule:\\ \\ v=v_0+g\times t\\ \\ \\ d=v_0\times t+\frac {g\times t^2}2\\ \\ \\ Calcule:\\ \\ v=3+10\times 3=33\frac ms\\ \\ d=3\times 3+\frac{10\times 3^2}2=54m\\ \\ [/tex]



[tex]3)Se~da:\\ \\ h=180m\\ \\ \tau=1s\\ \\ t_1=t_2\\ \\ g=10\frac m{s^2}\\ \\ v_0=?\frac ms\\ \\ \\ Formule:\\ \\ 1~corp:\\ \\ h=\frac {g\times t_1^2}2\\ \\ t_1=\sqrt\frac{2\times h}g\\ \\ \\[/tex]


[tex]2~corp:\\ \\ t_2=\tau+t\\ \\ t=t_2-\tau\\ \\ h=v_0\times t+\frac{g\times t^2}2\\ \\ h=v_0\times(t_2-\tau)+\frac{g\times(t_2-\tau)^2}2\\ \\ v_0\times(t_2-\tau)=h-\frac{g\times(t_2-\tau)^2}2\\ \\ v_0=\frac{2\times h-g\times(t_2-\tau)^2}{2\times(t_2-\tau)}\\ \\ Deoarece~t_1=t_2,~propun~sa~aflam~t_1~dupa~v_0:\\ \\ \\ Calcule:\\ \\ t_1=\sqrt\frac{2\times180}{10}=6s\\ \\ v_0=\frac{2\times 180-10\times(6-1)^2}{2\times(6-1)}=11\frac ms[/tex]



[tex]3)Se~da:\\ \\ h_1=4\times h_2\\ \\ \frac{v_1}{v_2}=?\\ \\ \\ Formule:\\ \\ h_1=\frac{-v_1^2}{-2\times g}\\ \\ Daca~nai~inteles~de~unde~sa~luat~formula:\\ \\ \\ \\ "Formula~de~baza~este:~d=\frac{\Delta v^2}{2\times a}\\ \\ d~reprezinta~inaltimea,~\Delta v^2~reprezinta~in~alta~forma:\\ \\ \Delta v^2=(v_2^2-v_1^2),~in~cazul~nostru~v_2~este~zero~(viteza~finala)\\ \\ "a"~in~formula~reprezinta~acceleratia.\\ \\ Deoarece~corpul~se~ridica~acceleratia~se~transforma~in~"-g"\\ \\ [/tex]

[tex]Poti~sa~inlocuiesti~si~vezi~ca~iti~da~aceeasi~formula\\ \\ P.s.~Formula~se~obtine~mai~usor~folosind~cele~2~energii,\\ \\ dar~deoarece~esti~la~asa~capitol~folosesc~aceasta~metoda"\\ \\ \\ \\ v_1=\sqrt{2\times g\times h_1},~analogic~pentru~corpul~2:\\ \\ v_2=\sqrt{2\times g\times h_2},~deci:\\ \\ \frac{v_1}{v_2}=\frac{\sqrt{2\times g\times h_1}}{\sqrt{2\times g\times h_2}},~matematica~ne~permite~sa~scriem:\\ \\ \frac{v_1}{v_2}=\sqrt\frac{2\times g\times h_1}{2\times g\times h_2}\\ \\ [/tex]

[tex]\frac{v_1}{v_2}=\sqrt\frac{4\times h_2}{h_2}\\ \\ \\ \frac{v_1}{v_2}=2[/tex]