Problem $15\mathrm{.}055-$ A rod connected to another rod and a collar

Knowing that at the instant shown, the angular velocity of rod $\backslash ($ B E $\backslash )$ is $\backslash (8\backslash$mathrm$\{$rad$\}/\backslash$mathrm$\{$s$\}\backslash )$ counterclockwise.

Problem $15\mathrm{.}055.$b $-$ Velocity of the collar

Determine the velocity of collar D$.$

The velocity of collar $\backslash ($ D $\backslash )$ is

$*$ mm$/$s$($

$*).$