For the quick return mechanism shown in the figure below, the following are known $-$

$O_2{O}_4=10cm,O_{2}A=5cm$ angle $O_4{O}_{2}A=60,{}_2=1ra\frac{d}{s}$ and ${}_2=0ra\frac{d}{s^2}$

a$.$ Calculate the angular velocity of link $4$ and the velocity of link $3$ w$.$r$.$t$.$ link $4$

b$.$ Explain the angular velocity of link $4$ intuitively.

c$.$ Calculate the angular acceleration of link $4$ and the acceleration of link $3$ w$.$r$.$t link $4$