Question

formule fizica clasa 7-a

Answer 1

$Viteza= \frac{Distanta}{Timp} , \ adica \ \boxed{v= \frac{d}{t} }, \ de \ unde \ scoatem \ si \ formulele \\ pentru \ distanta \ si \ timp: \ \boxed{d=v \cdot t}, \ iar \ \boxed{t= \frac{d}{v} }.\\ Constanta \ elastica= \frac{Forta }{Alungire} , \ adica \ \boxed{k= \frac{F_e}{\bigtriangleup \l} }, \ de \ unde \ scoatem: \\ \boxed{F_e=k \cdot \bigtriangleup l}, \ iar \ \boxed{\bigtriangleup l= \frac{F_e}{k} }.$
$Presiunea= \frac{Forta \ normala}{Aria \ suprafetei} , \ adica \ \boxed{p= \frac{F_n}{S} } \ de \ unde \ scoatem: \\ \boxed{F_n=p \cdot S}, \ iar \ \boxed{S= \frac{F_n}{p} }. \\ Presiunea \ in \ lichide=\boxed{\rho \cdot g \cdot h}. \\ Presiunea \ in \ gaze: \ \boxed{ \frac{F_2}{F_1} = \frac{S_2}{S_1}} . \\ Vase \ comunicante: \ \boxed{ \frac{h_2}{h_1} = \frac{\rho_1}{\rho_2} }. \\ Forta \ Arhimede: \ \boxed{F_A=P_1-P_2}, \ sau \ \boxed{F_A=\rho_l \cdot g \cdot V}.$ 
$Lucrul \ mecanic: \ \boxed{L=F_t \cdot d}, \ unde \ scoatem: \\ \boxed{F_t= \frac{L}{d} }, \ iar \ \boxed{d= \frac{L}{F_t} }. \\ Puterea \ mecanica: \ \boxed{P= \frac{L}{t} }, \ sau \ \boxed{P=F_t \cdot v}. \\ Energia \ cinetica: \ \boxed{E_c= \frac{m \cdot v^2}{2} }. \\ Energia \ potentiala: \ \boxed{E_p=m \cdot \ g \cdot h}. \\ Energia \ mecanica: \ \boxed{E=E_p+E_c}. \\ Parghie: \ \boxed{ \frac{F_1}{F_2} = \frac{b_2}{b_1} }. \\ Scripete: \ \boxed{F_1= \frac{F_2}{2} }.$
$Plan \ inclinat: \ \boxed{ \frac{G}{F} = \frac{l}{h}}. \\ Randamentul \ mecanic: \ \boxed{\eta= \frac{L_u}{L_t} \cdot 100 \%}, \ dar: \\ Lucrul \ util: \ \boxed{L_u=m \cdot g \cdot h}. \\ Lucrul \ total: \ \boxed{L_t=F \cdot l}.$