Respostas

2014-08-07T13:15:34-03:00
54 km/h / 3,6 = 15 m/s
36 km/h / 3,6 = 10 m/s
a = Vf - Vo/tf - to
a = 15 - 10/2
a = 5/2
a = 2,5 m/s²
2014-08-07T13:38:19-03:00
Converta km/h para m/s,

54/3,6=15m/s
3,6/3,6=10m/s

Agora aplique a formula da velocidade,

\boxed{v(t)=vo+a*t}

15=10+a*2

15-10=2*a

5/2=a

\boxed{a=2,5m/s^2}