An eaeroplane is to go along straight line from A to B, and back again. The relative speed with respect to wind is V. The wind blows perpendicular to line AB with speed v. The distance between A and B is l. The total time for the round trip is:

An aeroplane flies along a straight line from A to B with a speed v_(0) . A steady wind v is blowing if AB=l then a)total time for the trip is (2v_(0)l)/(v_(0)^(2)-v^(2)) if wind blows along the line AB b)total time for the trip is 2l/sqrt(v_(0)^(2)-v^(2)) ,if wind blows perpendicular to the line AB c)total time for the trip decrease because of the pressure of wind d)total time for the trip increase because of the presence of wind