Zamiana jednostek prędkości

1. Wyraź prędkość $108\frac{\text{km}}{\text{h}}$ w metrach na sekundę. 

$1\text{km}=1000\text{m}$
$1\text{h}=3600\text{s}$

$108\frac{\text{km}}{\text{h}}=108\cdot \frac{10\cancel{0}\cancel{0}\text{m}}{36\cancel{0}\cancel{0}\text{s}}{=}^3\bcancel{108}\cdot \frac{10\text{m}}{\bcancel{36}{}_1\text{s}}=3\cdot 10\frac{\text{m}}{\text{s}}=30\frac{\text{m}}{\text{s}}$

2. Wyraź prędkość $45\frac{\text{m}}{\text{s}}$ w kilometrach na godzinę.

$1\text{m}=\frac{1}{1000}\text{km}$
$1\text{s}=\frac{1}{3600}\text{h}$

$45\frac{\text{m}}{\text{s}}=45\cdot \frac{\frac{1}{1000}\text{km}}{\frac{1}{3600}\text{h}}=45\cdot \frac{36\cancel{0}\cancel{0}}{10\cancel{0}\cancel{0}}\frac{\text{km}}{\text{h}}{=}^9\bcancel{45}\cdot \frac{36}{{\bcancel{10}}_2}\frac{\text{km}}{\text{h}}=9\cdot 18\frac{\text{km}}{\text{h}}=162\frac{\text{km}}{\text{h}}$