Question

Two identical discs of the same radius R are rotating about their axes in opposite directions with the same constant angular speed $\omega .$ The discs are in the same horizontal plane. At time t = 0, the points P and Q are facing each other as shown in the figure. The relative speed between the two points P and Q is $v_r$. In one time period (T) of rotation of the discs, $v_r$ as a function of time is best represented by

• A.
• B.
• C.
• D.

Answer 1

The correct option is A



$V_r=|2vsin\theta |=|2vsin\omega t|$