A man can swim in still water with a speed of 2 m/s if he wants to cro...
Solution
Introduction
When a man swims in a river, he will be affected by the water current. Thus, he must swim in a direction that will enable him to cross the river in the shortest possible distance.
Calculation
Given that the speed of the man is 2 m/s and the water current speed is √3 m/s. The angle at which the man should swim can be calculated using trigonometry.
Let θ be the angle at which the man should swim, then the horizontal component of his velocity will be 2 cosθ and the vertical component will be 2 sinθ. The water current will have a horizontal component of √3 and no vertical component.
The resultant velocity of the man and the water current will be the vector sum of their velocities. Since the man wants to cross the river in the shortest possible distance, he must swim perpendicular to the water current.
Thus, the horizontal component of the man's velocity should be equal and opposite to the horizontal component of the water current. Therefore, 2 cosθ = √3 and cosθ = √3/2. This implies that θ = 30°.
Conclusion
In conclusion, the man should swim at an angle of 30° to the direction of the water current. This will enable him to cross the river in the shortest possible distance.