Use graphical method $(4$ marks$)-$ configuration diagram and relative method.

In a four$-$bar link mechanism, the dimensions of the link are $AB=60mm,BC=66mm,CD=56mm$ and $AD=100mm.$

At the instant when angle DAB$=60,$ the link $AB$ has an angular velocity $5ra\frac{d}{s}$ and retardation of $10ra\frac{d}{s^2}.$

Determine

a$.$ Angular acceleration of links $BC$ and CD$.(2$ marks$)$

b$.E$ is at midpoint or $33$ mm from B$.$ Linear acceleration of points E$.(2$ marks$)$