Question

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

• A. $\frac{1}{10}m/s$
• B. $\frac{1}{15}m/s$
• C. 10 m/s
• D. 15 m/s

Answer 1

The correct option is B $\frac{1}{15}m/s$

Differentiating the mirror equation and finding the velocity of image. which comes out to be -$\frac{1}{15}$. The negative sign just shows the direction of velocity of image.