^Crossing a river

^Crossing a river

Suppose a person start rowing his boat from point O with velocity v_br (w.r.t. river i.e. without considering the effect of water) towards point S in order to cross a river of width ‘w’ flowing at a speed ‘v_r’ towards x axis. Let under the effect of river current boat has net velocity the boat v_b (w.r.t. ground i.e. resultant v_br & v_r) & he reaches point R, then the distance SR covered downstream (i.e. distance along the stream) is called drift.