Dane:

$m=3t=3000kg$

$t=2\min =120s$

$v_p=50\frac{km}{h}=50\cdot \frac{10\sout{00}m}{36\sout{00}s}=\frac{500}{36}\frac{m}{s}=\frac{125}{9}\frac{m}{s}$