The speed of a swimmer in still water is 20   m   s - 1 . The speed of river water is 10   m   s - 1 and is flowing due east. If he is standing on the south bank and wishes to cross the river along the shortest path, the angle at which he should make his strokes with respect to the north is given by

Step-by-step solution

For reaching just apposite bank of the river the net velocity at the river should be zero that means v sin θ   =   v e l o c i t y   o f   r i v e r sin θ = v e l o c i t y   o f   r i v e r v e l o c i t y   o f   s w i m m e r sin θ = 10 20 = 1 2 θ = 30 ° 30 ° west of north