Question

A plane mirror is placed along the $y$ axis such that the $x$ axis is normal to the plane of the mirror. The reflecting surface of the mirror is towards the negative $x-$ axis. The mirror moves in positive $x-$direction with a uniform speed $5m/s$ and a point object $p$ is moving with a constant speed $3m/s$ in the negative $x-$ direction. The speed of the image with respect to mirror is

• A. $8m/s$
• B. $16m/s$
• C. $5m/s$
• D. $10m/s$

Answer 1

The correct option is A $8m/s$

From the given figure we have

$v_i=2v_m+v_o$

$=2\times 5+3=13m/s$

Speed of the image w.r.t mirror

$=13-5=8m/s$