To find the resultant motion or change of position of the man who swims across the river, we can use vector addition. The man's motion can be broken down into two components: one along the river's flow direction (horizontal) and the other perpendicular to the river's flow (vertical).

Let's assume: Distance swum by the man in the river = 0.6 km Distance covered by the river's flow = 0.4 km

The man's resultant motion or change of position will be the vector sum of these two motions.

Horizontal Component (across the river): Since the man is swimming directly across the river, the horizontal component of his motion is the distance swum by the man: 0.6 km.

Vertical Component (along the river's flow): The vertical component is the distance covered by the river's flow: 0.4 km.

Resultant Motion: To find the resultant motion or change of position, we can use the Pythagorean theorem for right triangles, where the hypotenuse (resultant) is the vector sum of the horizontal and vertical components.

Resultant^2 = (Horizontal Component)^2 + (Vertical Component)^2 Resultant^2 = (0.6 km)^2 + (0.4 km)^2 Resultant^2 = 0.36 km^2 + 0.16 km^2 Resultant^2 = 0.52 km^2

Resultant = √(0.52) km ≈ 0.7217 km