Question

Find the velocity of image.

• A. $-19\hat{i}+4\hat{j}$
• B. $-11\hat{i}$
• C. $-11\hat{i}+4\hat{j}$
• D. $-8\hat{i}+4\hat{j}$

Answer 1

The correct option is A $-19\hat{i}+4\hat{j}$

From the mirror frame of reference,


y-component of image velocity $=5sin53=4\hat{j}$

(y component doesn't change by reflection)

x-component of velocity of mirror $=-8\hat{i}$

x-component of image velocity $=-(5cos53+8)\hat{i}=-(3+8)\hat{i}=-11\hat{i}$

Now in the lab (ground) frame of reference,

x-component of image velocity $=-11-10cos37=-19\hat{i}$

So image velocity $=-19\hat{i}+4\hat{j}$