A solid disc of radius $$r$$ rolls without slipping on a horizontal floor with angular velocity $$\omega $$ and angular acceleration $$\alpha $$. The magnitude of the acceleration of the point of contact on the disc is

In the mechanism given below, if the angular velocity of the eccentric circular disc is $$1$$ rad/s, the angular velocity (rad/s) of the follower link for the instant shown in the figure is

Note : $$All$$ $$dimensions$$ $$are$$ $$in$$ $$mm$$

A double - parallelogram mechanism is shown in the figure. Note that PQ is a single link. The mobility of the mechanism is

There are two points P and Q on a planar rigid body. The relative velocity between the two points