To travel straight north across a river with an eastward current, the boat must be directed northwest to counteract the current and reach the opposite bank directly.
The question involves the concept of vector addition in the context of a boat traveling across a river with a current. To travel straight north across a river that has an eastward current of 2 m/s, while the boat's speed in still water is 6 m/s, the boat must be aimed upstream, in a northwesterly direction. By pointing the boat northwest, the downstream current is counteracted, allowing the boat to reach the northern bank directly opposite its starting point on the south bank. The exact angle to aim at can be found by using vector components and trigonometric functions to reach an intended destination.