[填空题]
A and B rowers, who can row at the same speedr cj .o ;4z, g-mg7b9(f.ogm/kxkh fnu in still water, set off awq:jzql7d28c*ct6u +ozd/j w zm. 1ctcross a river at the dltwco.7cjj q:z/qt6* zw1 c2+ dz m8usame time. A heads straight across and is pulled downstream somewhat by the current. The B heads upstream at an angle so as to arrive at a point opposite the starting point. Which rower reaches the opposite side first?
参考答案: A
本题详细解析: Both rowers need to cover the samev xypu- 5wz. u kr6;eg+n5q/hz "cross river" distance. The rower with the greatest speed in the "cross river" direction will be the one that reaches the other side first. The current has no bearing on the problem because the current doesn't help either of the boats move across the river. Thus the rower heading straight across will reach the other side first. All of his rowing effort has gone into crossing the river. For the upstream rower, some of his rowing effort goes into battling the current, and so his "cross river" speed wx -z y+wn6uk;5 gv5u /pqh.ezrill be only a fraction of his rowing speed.
