Question

A torch producing a straight light beam falling on a plane mirror at an angle ${60}^o$. The reflected beam make a spot P on the screen along Y-axis. If at $t=0$, mirror starts rotating about the hinge A with an angular velocity $\Omega =1^o$ per second clockwise. Find the speed of the spot on screen after time $t=15s.$

Answer 1

$v=\sqrt{2}{v}_0$

$=\sqrt{2}$ (double of the speed of mirror)

=$\sqrt{2}(2^0$ per sec)

=$\sqrt{2}{2}^0$ per sec