Acceleration Analysis of Pure Rolling

Q. A solid disk 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

1. Zero
2. $r\alpha$
3. $\sqrt{(r\alpha {)}^2+(r{\omega }^2{)}^2}$
4. $r{\omega }^2$

Q. Blocks P and Q are released from rest in the poitions shown. Neglect friction between all surfaces, i.e., both blocks can translate freely. Then the direction of the acceleration of blcok Q (i.e. $a_Q$) is

1. 
2. 
3. 
4.