A mirror of weight 75N is hung by a cord from a... - JAMB Physics 2006 Question
A mirror of weight 75N is hung by a cord from a hook on the wall. If the cord makes an angle of 30o with horizontal, the tension in the cord is
A
100N
B
1500N
C
250N
D
150N
correct option: d
For vertical equilibrium, we have
2Ty = 75N
But Ty/T = adj/hyp = cos 60o
∴ Ty = T Cos 60o
=> 2Ty = 2Tcos 60o = 75N
2 x T x 0.5 = 75 => T = 75N
∴ Total tension in the rope = 2T.
= 2 x 75 = 150N
2Ty = 75N
But Ty/T = adj/hyp = cos 60o
∴ Ty = T Cos 60o
=> 2Ty = 2Tcos 60o = 75N
2 x T x 0.5 = 75 => T = 75N
∴ Total tension in the rope = 2T.
= 2 x 75 = 150N
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