Final answer:
The steady speed of a river refers to the constant flow rate of the river's current, which can be calculated using the relative motion of objects within the river.
Step-by-step explanation:
The steady speed of a river, also known as the river current's speed, is the constant speed at which water in the river flows in a given direction. This speed can be determined by analyzing the motion of objects, such as boats or swimmers, moving relative to the river. For example, if two speedboats are traveling at the same speed relative to the water but appear to be moving at 4.0 m/s and 5.0 m/s relative to an observer on the riverbank, the river's steady speed can be calculated by considering the differing speeds due to the current's influence. Additionally, when someone rows a boat or swims across the river, they will be affected by this steady current, which can be understood through concepts such as relative velocity and displacement.