A weight w is suspended from the midpoint of a rope, whose ends are at the same level. In order to make the rope perfectly horizontal, the force applied to each of its ends must be:
A)less than w
B)equal to w
C) equal to 2w
D) infinitely large
Correct Answer:
D
Solution :
For equilibrium of body \[mg=2T\cos \theta \] \[\therefore \] \[T=\frac{mg}{2\cos \theta }\] For the string to be horizontal, \[\theta \to {{90}^{o}}\] \[\therefore \] \[T=\frac{mg}{2\cos {{90}^{o}}}\] \[\Rightarrow \] \[T\to \infty \]