Respostas

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2013-09-20T16:57:00-03:00
A) Fr² = F1² + F2² + 2*F1*F2*cos(90°)

Fr² = 12² + 16² + 2*12*16*0
Fr² = 144 + 256
Fr² = 400

Fr =  \sqrt{400}

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Fr = 20N
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b) Fr = m * a

20 = 4 * a

20/4 = a

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a = 5m/s²
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