When an object is kept at a distance of $30\, cm$ from a concave mirror,the image is formed at a distance of $10\, cm$ from the mirror. If the object is moved with a speed of $9\, cm/s$,the speed (in $cm/s$) with which the image moves at that instant is:

There are two plane mirrors with reflecting surfaces facing each other. The mirrors are moving with speed $v$ away from each other. $A$ point object is placed between the mirrors. The velocity of the $n$-th image will be

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

$A$ point object on the principal axis at a distance $1.5\, cm$ in front of a concave mirror of radius of curvature $20\, cm$ has velocity $2\, mm/s$ perpendicular to the principal axis. The velocity of image at that instant will be.....$mm/s$

The speed at which the image of a luminous point object is moving,if the luminous point object is moving at speed $v_0$ towards a spherical mirror along its axis,is (Given: $r =$ radius of curvature,$u =$ object distance):

$A$ point object is moving on the principal axis of a concave mirror of focal length $24\;cm$,towards the mirror. When it is at a distance of $60\;cm$ from the mirror,its velocity is $9\;cm/sec$. What is the velocity of the image at that instant?