Question

Imagine yourself standing in front of a plane mirror. You then start to walk towards the mirror at 1.8 ms -1. How fast will your image in the mirror will approach you? (A) 1.8 m/s (B) 3.6 m/s (C) 0.9 m/s (D) 4.5 m/s

Answer 1

The correct answer is option 'b':
`3.6m/s`

Step-by-step explanation:

As we know that the image formed by a plane mirror is at same distance behind the mirror as the object is placed in front of the mirror.

Hence we can conclude that the speed of the image as it moves towards the mirror is equal to the speed of the object as it moves towards the mirror.

Thus the relative speed of the object and the image can be calculated as

`V_(io)=V_(i)-V_(o)\\\\`

where

`V_(i)` is the speed of the image towards mirror

`V_(o)` is the speed of the object towards mirror

Applying values we obtain the relative speed as

`V_(io)=1.8m/s-(-1.8m/s)\\\\V_(io)=3.6m/s`