question_answer

A wire elongates by i mm when a load W is hanged from it. If the wire goes over a pulley and two weights W each are hung at the two ends, the elongation of the wire will be (in mm)

A) \[2\ell \]

B)                                zero

C) \[\ell /2\]                                                                                                                                                                  

D) \[\ell\]

Correct Answer: D

Solution :

In first case  and in second case As tension in the wire in both the cases are equal therefore elongation in the wire will be equal.