A car is fitted with a convex side-view mirror of focal length `20 cm` `A` second car `2.8 m` behind the first car is overtaking the first car at a relative of `15 m//s`. The speed of the image of the second car as seen in the mirror of the first one is :

Options

A. 10 m/s
B. 15 m/s
C. `(1)/(10) m//s`
D. `(1)/(15) m//s`

Answer

D

Explanation

Velocity of image = `-m^(2)V_(0) = - ((f)/(f-u))^(2) V_(0)`
= `-((20)/(20 -(-280)))^(2) (15) = -(1)/(15) m//s`