[tex]dane:\\v_1 = 340\frac{m}{s}\\I_1 = 170 \ cm = 1,7 \ m\\v_2 = 1500\frac{m}{s}\\szukane:\\I_2 = ?[/tex]
[tex]\frac{v_1}{I_1} = \frac{v_2}{I_2}\\\\v_1\cdot I_2 = v_2 = I_1 \ \ /:v_1\\\\I_2 = \frac{v_2}{v_1}\cdot I_1\\\\I_2 = \frac{1500\frac{m}{s}}{340\frac{m}{s}}\cdot1,7 \ m = 15000\cdot 0,005 \ m\\\\I_2 = 7,5 \ m[/tex]