Respostas

2014-03-09T17:46:49-03:00
 h = g * t²/2
80 = 10 * t² / 2
2 * 80 = 10t²
160 = 10t²
t² = 160/10
t² = 16= raiz de 16  
t= 4s

V= g * t
V= 10 * 4
V= 40m/s