Given complexity, let's just present the from such problems: Step 3: The interesting twist In many Bedford problems, students assume ( v_B = v_A ) or ( v_B = 2v_A ). But due to the changing angle ( \theta ), the relationship is:
Therefore:
Thus: Rope from fixed pulley to A shortens at rate ( v_A ). Rope from left fixed point to B lengthens at rate ( v_B \cos\theta ). Since total rope length constant: ( v_A = v_B \cos\theta ).