Question

An observer moves towards a stationary plane mirror at a speed of 4$m{s}^{-1}$. Determine the velocity of the image with respect to the mirror:

• A. 8$m{s}^{-1}$
• B. 4$m{s}^{-1}$
• C. 2$m{s}^{-1}$
• D. 16$m{s}^{-1}$

Answer 1

The correct option is B 4$m{s}^{-1}$

In case of plane mirror,magnification is unity.Hence m=1

$\frac{-v}{u}=1$

-v=u.

Differentiating above equation w.r.t t

$\frac{dv}{dt}=\frac{du}{dt}$

Hence velocity of object w.r.t mirror is equal to negative velocity of image w.r.t mirror.