Respostas

2014-01-09T11:18:39-02:00
S = So + Vot + at² / 2

parte do repouso , logo Vo = 0

S - So = Vot + at² / 2

S - So = ΔS

40  = 0 + a.4² / 2

40 = 8a
a = 40 / 8 ~> 5 m/s²

F = m .a

F = 10 . 5 = 50 N


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