Respostas

2014-07-10T12:29:37-03:00
Bloco A:

Fr = m . a
F - T = 5 . a
40 - T = 5a
-T = 5a - 40
T = -5a + 40

Bloco B:

Fr = m . a
T - P . sen30° = 20 . a
T - m . g . 0,5 = 20a
T - 100 = 20a
T = 20a + 100

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-5a + 40 = 20a + 100
-5a - 20a = 100 - 40
-25a = 60
a = -2,4 m/s²
|a| = 2,4 m/s²