The rod oa rotates clockwise with a constant angular velocity of 6

  

The rod OA rotates clockwise with a constant angular velocity of 6 rad/s. Two pin-connected slider blocks, located at B, move freely on OA and the curved rod whose shape is a limacon described by the equation r=200(2?cos?)mm. Determine the magnitude of the acceleration of the slider blocks at the instant ? = 155 degrees.