Question
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A swimmer which can swim with velocity 
relative to water, dives into the river perpendicular to the direction of flow to cross the river. What is the displacement of swimmer when he reaches opposite side of the river?
Solution
Width if the river = d km
Rate of flow of river = v1 m/s
Rate of flow of swimmer = v2 m/s
Given that, the swimmer is diving in a direction perpendicular to the flow of river, to cross the river.
Therefore, the displacement of the swimmer when he reaches the opposite side of the river is given by,
