A mild steel wire of length and cross-sectional area is stretched, well within its elastic limit, horizontally between two pillars. A mass of is suspended from the mid-point of the wire. Calculate the depression at the midpoint.

Water pressure at the bottom is given as,

Pa

Initial volume of the steel ball is given as

Bulk modulus of steel is known as

Let be the change in the volume of the ball on reaching the bottom of the trench.

Bulk modulus,

Hence, on reaching the bottom of the trench, volume of the ball changes by .