Please start the solutions with the general equations.

$3-$ At the instant shown, roller C has a velocity of $250$mm$//$s up the channel. Determine the angular velocities of both bars and the velocity of pin B at this instant.

Comprehension $($Free Body Diagram or Diagram Sketch$)$

Knowledge $($Equations that Governing the Phenomenon$)$

Application $($Solution Procedure, all computations$)$