A weight \[mg\] is suspended from the middle of a rope whose ends are at same level. If the rope is no longer horizontal, the minimum tension required to completely straighten the rope will be
A)\[mg\]
B)\[\sqrt{mg}\]
C) Infinite
D) zero
Correct Answer:
C
Solution :
The given situation can be shown as from figure \[2T\sin \theta =mg\] or \[T=\frac{mg}{2\sin \theta }\] when rope is straight,\[\theta ={{0}^{o}}\] \[\therefore \] \[T=\frac{mg}{2\sin 0}=\infty \] (infinite)