At what time, does the speed become constant?

Explanation: For an object to achieve constant speed in a specific period of time, it has to have constant current speed and to be moving in the same direction, meaning that the object has to move in one direction without taking turns so that the speed doesn't decrease or increase. Constant speed is measured when an object travels equal distance for equal amount of time.

water at room temperature is flowing through a pipe with pressure taps located 10 ft apart along one section of the pipe, which are connected to a mercury (s=13.6) manometer.