Two persons are holding a rope of negligible weight tightly at its ends so that it is horizontal. A 15kg weight is attached to the rope at the mid-point. The minimum tension required to completely straighten the rope is
Two persons are holding a rope of negligible weight tightly at its ends so that it is horizontal. A 15kg weight is attached to the rope at the mid-point. The minimum tension required to completely straighten the rope is
The correct option is D Infinitely large
When a string is fixed horizontally (by clamping its free ends) and loaded at the middle, then for the equilibrium of point P. 
2Tsinθ=Wi.e.,T=W2sinθ
Tension in the string will be maximum when sin θ is minimum, i.e.,θ=00orsinθ=0andthenT=∞ However, as every string can bear a maximum finite tension (lesser than breaking strength). So this situation cannot be realised practically. We conclude that a string can never remain horizontal when loaded at the middle however great the tension when loaded at the middle howsoever great the tension be applied.
Infinitely large
When a string is fixed horizontally (by clamping its free ends) and loaded at the middle, then for the equilibrium of point P.
2Tsinθ=Wi.e.,T=W2sinθ
Tension in the string will be maximum when sin θ is minimum, i.e.,θ=00orsinθ=0andthenT=∞ However, as every string can bear a maximum finite tension (lesser than breaking strength). So this situation cannot be realised practically. We conclude that a string can never remain horizontal when loaded at the middle however great the tension when loaded at the middle howsoever great the tension be applied.
