89. A 20.0 kg uniform plank is supported by the floor at one end and by a vertical rope at the other as shown in the figure below. A 50.0 kg mass person stands on the plank a distance three-fourths of the length plank from the end on the floor. What is the tension in the rope? 
(A) 165.5N
(B) 265.5N
(C) 365.5N
(D) 465.5N
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統計: A(0), B(0), C(1), D(3), E(0) #2319906
統計: A(0), B(0), C(1), D(3), E(0) #2319906