Respostas

2014-04-02T18:14:52-03:00
d=4,9t^2\\122,5=4,9t^2\\t^2=\frac{122,5}{4,9}\\t^2=25\\t= \sqrt{25}

\boxed{\boxed{t=5~s}}

Tempo estimado de 5 segundos
5 4 5