56. Problem 13.55P (HRW) A 103 kg uniform log hangs by two steel wires, A and
B, both of radius 1.20 mm. Initially, wire A was 2.50 m long and
2.00 mm shorter than wire B. The log is now horizontal. What forces are
exerted on it by (a) wire A and (b) wire B? (c) What is the
ratio
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Solution: Click For PDF Version Let W be the weight of the log. Let the initial lengths of the wires
A and B be
and Let
In the following we will approximate Young’s modulus of steel
From Hook’s law of elasticity, we have
We, therefore, have We thus find (c) And, (a) and (b) Force exerted on wire A is
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