Ray Optics

A point object is moving uniformly towards the pole of a concave mirror of focal length \(25 \mathrm{~cm}\) along its axis as shown below. The speed of the object is \(1 \mathrm{~ms}^{-1}\). At \(t=0\), the distance of the object from the mirror is \(50 \mathrm{~cm}\). The average velocity of the image formed by the mirror between time \(t=0\) and \(t=0.25 \mathrm{~s}\) is