Three swimmers can swim equally fast relative to the water. They have a race to see who can swim across a flowing river in the least time. Swimmer A swims perpendicular to the current and lands on the opposite shore downstream, because the current has swept him in that direction. Swimmer B swims upstream at angle to the current, so that when she reaches the other side, she is straight across from where she started. Swimmer C swims downstream at an angle theta in an attempt to take advantage of the current. Who crosses the river in the least time?

I think its swimmer B because a and c are swimming downstream when they are trying to go across

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction 

C. hope this . : )