Respostas

2013-10-02T13:35:56-03:00
S = So + Vot + g/2.t²

S1 = 80 + 0t + 5t²              S2 = 20 + 0t + 5(t + 1)²                
S1 = 80 + 5t²                     S2 = 20 + 5(t + 1)²

80 + 5t² = 20 + 5(t + 1)²
80 + 5t² = 20 + 5(t² + 2t + 1)
80 + 5t² = 20 + 5t² + 10t + 5
80 - 20 - 5 = 5t² - 5t² + 10t
55 = 10t
t = 55/10
t = 5,5s       
15 2 15