A particle is moving at a constant speed V from a large distance towards a concave mirror of radius R along its principal axis. Find the speed of the image formed by the mirror as a function of the distance x of the particle from the mirror.


Radius of the concave mirror= R

Focal length of the mirror,

Velocity of the particle,

Let velocity of the image is represented as V’

The distance of the object from the mirror, u= -x

Using mirror equation,