Respuestas

2013-11-21T10:17:52+01:00
90 Km/h = 90000 / 3600 = 25 m/sg

120 Km/h = 120000 / 3600 = 33,33 m/sg

vf = vo + a. t 

33,33 = 25 + 4 . t

4t = 8,33

t = 8,33 / 4 = 2,08 sg