The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity 1 rad/s in the clockwise direction and the link OB turns with angular velocity 2 rad/s in the anti-clockwise direction, then the rubbing velocity at the pin joint O is

The two links OA and OB are connected by a pin joint at O. If the link

1.	The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity 1 rad/s in the clockwise direction and the link OB turns with angular velocity 2 rad/s in the anti-clockwise direction, then the rubbing velocity at the pin joint O is
A.	<sub>1</sub>. <sub>2</sub>.r
B.	( <sub>1</sub>- <sub>2</sub>)r
C.	( <sub>1</sub>+ <sub>2</sub>)r
D.	( <sub>1</sub>- <sub>2</sub>)2r
Answer» D. ( <sub>1</sub>- <sub>2</sub>)2r