promien kola wynosi 40 cm ile obrotow na sekundę wykonuje kolo gdy smochod jedzie z predkoscia 90km/h

[latex]dane:\r = 40cm = 0,4m\v = 90km/h = 25m/s\t = 1s\szukane:\n = ?[/latex] [latex]v = 2 pi rf\\f = frac{v}{2 pi r} = frac{25m/s}{2 * 3,14 * 0,4m} = 9,95Hz\\f = frac{n}{t}[/latex] [latex]n = f * t = 9,95/s * 1s = 9,95[/latex] [latex]n = 9[/latex]