Respostas

2013-09-06T21:31:40-03:00
S = So + Vot + g/2.t²
0 = 0 + 30t - 5t²
- 5t² + 30t = 0
t(- 5t + 30) = 0
- 5t +30 = 0
- 5t = - 30
t = - 30/- 5
t = 6s