Example $7\mathrm{.}13.$ The dimensions of the mechanism, as shown in Fig. $7\mathrm{.}30,$ are as follows :

$AB=0\mathrm{.}45m$;$BD=1\mathrm{.}5m$:$BC=CE=0\mathrm{.}9m$

The crank A B turns uniformly at $180$ r$.$p$.$m$.$ in the clockwise direction and the blocks at $D$ and $E$ are working in frictionless guides.

Draw the velocity diagram for the mechanism and find the velocities of the sliders $D$ and $E$ in their guides. Also determine the turning moment at $A$ if a force of $500$ N acts on $D$ in the direction of arrow $x$ and a force of $750$ N acts on $E$ in the direction of arrow $Y.$

Solution. Given : $N_{BA}=180r.p.m.$ or ${}_{BA}=2\frac{180}{60}=18\mathrm{.}85ra\frac{d}{s}$