Răspuns:
De 16 ori
Explicație:
[tex]\displaystyle{ Ec_{1} = \frac{m_{1} \cdot v_{1}^{2} }{2} }[/tex]
[tex]\displaystyle{ Ec_{1} = \frac{m_{1} \cdot 2^{2} }{2} = \frac{m_{1} \cdot 4}{2} = 2 \cdot m_{1} }[/tex]
[tex]\displaystyle{ Ec_{2} = \frac{m_{2} \cdot v_{2}^{2}}{2} }[/tex]
[tex]\displaystyle{ Ec_{2} = \frac{m_{2} \cdot 8^{2}}{2} = \frac{m_{2} \cdot 64}{2} = 32 \cdot m_{2} }[/tex]
[tex]\displaystyle{ Ec_{1} = Ec_{2} \rightarrow 2 \cdot m_{1} = 32 \cdot m_{2} }[/tex]
[tex]\displaystyle{ m_{1} = 16 \cdot m_{2} }[/tex]
