Question

An object and a concave mirror are approaching each other with velocities $10 m/s$ and $5 m/s$ as shown in figure. The velocity of image of object at the instant shown in figure is

• A. $65 m/s \, $ $\hat{i}$
• B. $65 m/s$ $\left(- \hat{i}\right)$
• C. $40 m/s$ $\hat{i}$
• D. $40 m/s$ $\left(- \hat{i}\right)$

Answer 1

Answer: (B)

The formula for velocity of image is given by :
$=V_{I m}=\frac{f}{f - u}=\frac{- 10}{- 10 + 15}=-2$
$\therefore V_{I m}=-4 \, V_{O m}$
Therefore, $\vec{V}_I-5(-\hat{i})=-4\{10 \hat{i}+5 \hat{i}\}$
$\Rightarrow \overset{ \rightarrow }{V}_{I}=-65 \, \hat{i}$