Question

Q.28
Q.20
A car is moving towards a plane mirror at a
speed of 30 m/s. Then the relative speed of
its image with respect to the car will be-
(A) 30 m/s
(B) 60 m/
(C) 15 m/s
(D) 45 m/s​

Answer 1

Answer:

"OPTION B 60 m/s"

Explanation:

x’ = -x, where x is position of observer and x’ is position of the image.

With mirror at 0.

So, if dx/dt = 2 m/s, dx’/dt = -dx/dt = - 30m/s.

using the classical formula for relative speed,

Vrel = dx’/dt - dx/dt = -2dx/dt = -60m/s.

So, the image is approaching the observer at 60 m/s.

Hence option B is the right answer