Determine the time taken by B to travel downward 50 cm from the moment it's released. Assume the pulley rotates without slipping.

Answer:
To determine the time taken by object B to travel downward 50 cm, we need more information about the system. Specifically, we need to know the mass of object B, the radius of the pulley, and any other relevant details that might affect the motion.
Please provide additional information about the setup or clarify any parameters necessary for the calculation.