Odpowiedź :
[tex]Dane:\\\lambda = 1,2 \ m\\f = 2 \ Hz = 2 \frac{1}{s}\\Szukane:\\v = ?\\\\\\v = \frac{\lambda}{T}\\\\ale \ \ T = \frac{1}{f}\\\\v = \lambda\cdot f\\\\v = 1,2 \ m\cdot2 \frac{1}{s}\\\\\boxed{v = 2,4\frac{m}{s}}[/tex]
[tex]Dane:\\\lambda = 1,2 \ m\\f = 2 \ Hz = 2 \frac{1}{s}\\Szukane:\\v = ?\\\\\\v = \frac{\lambda}{T}\\\\ale \ \ T = \frac{1}{f}\\\\v = \lambda\cdot f\\\\v = 1,2 \ m\cdot2 \frac{1}{s}\\\\\boxed{v = 2,4\frac{m}{s}}[/tex]