[tex]\displaystyle\\ 21)\\ \text{Daca balanta este la echilibru, atunci: }\\ m_1 = m_2\\ \text{Daca corpurile sunt din materiale diferite, atunci: }\\ \rho_1 \neq \rho_2\\ V_1 \neq V_2\\\\ \text{Relatia dintre masa, densitate si volum este: }\\\\
\rho = \frac{m}{V} ~~\Longrightarrow~~ m = \rho V~~\Longrightarrow~~V= \frac{m}{\rho}\\\\ [/tex]
[tex]\displaystyle\\
\text{Rezolvare:}\\\\
a)\\
V_1 \ \textgreater \ V_2~\text{daca}~\rho_1\ \textgreater \ \rho_2~\text{Fals, deoarece }\rho~si~V\text{ sunt invers proportionale}\\\\
b)\\
V_1\ \textless \ V_2~\text{daca}~\rho_1\ \textgreater \ \rho_2~\text{Adevarat }\\\\
c)\\
\rho_1V_1=\rho_2V_2~\text{Adevarat deoarece: }m_1= m_2~\text{si}~m = \rho V\\\\
d)\\
\frac{m_1}{V_1} \ \textgreater \ \frac{m_2}{V_2} ~\text{daca}~\rho_1 \ \textgreater \ \rho_2 ~\text{Adevarat deoarece }~\rho = \frac{m}{V}\\\\
e)\\
\frac{m_1}{V_1} \ \textless \ \frac{m_2}{V_2} ~\text{daca}~\rho_1 \ \textgreater \ \rho_2 ~\text{Fals }[/tex]
