Q7 of 29 Page 65

A rectangular frame is to be suspended symmetrically by two strings of equal length on two supports (Fig. 9.2). It can be done in one of the following three ways;

(a)


(b)


(c)


The tension in the strings will be



Let (T) be the tension on the wires and (M) be the mass of the block, then


For this case, 2T = Mg


T = Mg/2



For this case, the sine components are cancelled.


2Tcosθ = Mg


T = Mg/2cosθ


The cosine of any angle will vary from 0 to 1 with 1 reaching at 0˚ which would then become the previous case. In this since the cosine will be less than one Tension in this case will be more than the previous case when the strings are vertical.


Thus, tension is least in this case.

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