. Two persons are holding a rope of negligible

weight tightly at its ends so that it is horizontal.

A 15 kg weight is attached to the rope at the mid point which now no longer remains horizontal.

The minimum tension required to completely straighten the rope is:

A: 15 kg

B: 15/2 kg

C: 5 kg

D: Infinitely large


Best Answer


The tension required to bring the string into horizontal position can be found out using the formula, 2T sin x=mg

The following equation is true for the body which attains equilibrium. 

And also, when the body will be in equilibrium the angle formed will be 0.

So, T=mg2sin x 

When x=0

We have, T=mg /2sin (0)

Since sin 0=0

The amount of tension will be infinite.

Final Answer

Option D is the correct choice.


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