Respostas

2014-09-03T16:59:43-03:00
8 km = 8.000 m
Vm = 20 m/s
t = ?

Vm = \dfrac{\Delta S}{\Delta t} \to t=\dfrac{\Delta S}{Vm} \\ \\ \\ t = \dfrac{800\not0}{2\not0} \\ \\ \boxed{t = 400 \ s}