Q7.28  A disc rotating about its axis with angular speed \omega _{0} is placed lightly (without any translational push) on a perfectly frictionless table. The radius of the disc is R . What are the linear velocities of the points  AB and C on the disc shown in Fig. 7.41? Will the disc roll in the direction indicated ?


Answers (1)

Let the angular speed of the disc is  \omega.

So the linear velocity can be written as    v\ =\ \omega r

(a)  Point A:-  

                               The magnitude of linear velocity is \omega r and it is tangentially rightward.

(b)  Point B:-  

                                The magnitude linear velocity is \omega r and its direction is tangentially leftward.

 (c) Point C:-  

                                The magnitude linear velocity is   \frac{ \omega r}{2}  and its direction is rightward.


The disc cannot roll as the table is frictionless.