A wire elongates by l 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, then the elongation of wire will be (in mm).

Options

A. l
B. 2l
C. zero
D. `l/2`

Answer

A

Explanation

In connected system, T =`(2W_(1)W_(2))/(W_(1)+W_(2))`
`rArrT=(2xxWxxW)/(2W)`=W
This tension produces extension 1 mm in the string. So correct choice is (a).