question_answer

A weight w is suspended from the mid- point of a rope, whose ends are at the same level. In other 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 2 w                     

D) infinitely large

Correct Answer: D

Solution :

For equilibrium of body \[mg=2T\cos \theta \] \[T=\frac{mg}{2\cos \theta }\] For the string to be horizontal, \[\theta =\text{9}0{}^\circ \] \[T=\frac{mg}{2\cos {{90}^{\circ }}}\] \[\Rightarrow \]               \[T=\infty \]