The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ω₁ rad/s in the clockwise direction and the link OB turns with angular velocity ω₂ rad/s in the clockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)

• A. (ω₁ - ω₂)r
• B. (ω₁ + ω₂)r
• C. ω₁.ω₂.r
• D. (ω₁ - ω₂)2r

Answer: (A)