Răspuns:
[tex]ec = \frac{m \times {v}^{2} }{2} \\ ec = \frac{3.6 \times {5.4}^{2} }{2} \\ ec = \frac{3.6 \times 29.16}{2} \\ ec = \frac{104.976}{2} \\ ec = 52.488 \: j[/tex]
[tex]52.488 = \frac{m \times {8}^{2} }{2} \\m \times 64 = 52.488 \times 2 \\ 64m = 104.976 \\ m = \frac{104.976}{64} \\ m = 1.64 \: kg[/tex]
Sper că te-am ajutat! ^^
