When a weight `W` is hung from one end of a wire of length `L` (other end being fixed), the length of the wire increases by `l`. If the same wire is passed over a pulley and two weights `W` each are hung at the two ends,what will be the total elongation in the wire?

Explanation

In second case the tension is double, but the original length is reduced to half. So the extension in the second case is the same as in the first case.