Final answer:
The breakaway cable on the MHU-141 trailer activates the emergency brakes if the trailer disconnects from the towing vehicle, ensuring it does not become a hazard.
Step-by-step explanation:
The purpose of the breakaway cable on the MHU-141 trailer is a crucial safety feature designed to engage the trailer's emergency brake system in the event that the trailer becomes accidentally disconnected from the towing vehicle. If the trailer were to separate, the breakaway cable would be pulled, which in turn activates the emergency brake system to bring the trailer to a controlled stop, preventing it from becoming a hazard to others on the road.