Question

A recantangular frame is to be suspended symmetrically by two strings of equal length on two supports (figure).It can be done in one of the following three ways:

A. the same in all cases
B. least in (i)
C. least in(ii)
D. least in (iii)

Answer 1

Correct Answer - C
Let M be the mass of rectangular frame and `theta` be the angle which the tension T in the string makes with the horizontal as shown in the figure.
`:. " " 2T sintheta=Mg`
or `T=(Mg)/(2sintheta)`
or `Tinfty(1)/(sintheta)`
T is least if `sintheta` has maximum value i.e., `sintheta = 1 = sin90^(@)`. Thus optoin (c) is correct.