# Homework Help: I Need Helppp!

1. Sep 14, 2004

### Sharayah

A swimmer wants to cross a river, from point A to point B. The distance (from A to C) is 200 m, the distance (from C to B) is 150 m, and the speed of the current in the river is 5 km/h. Suppose that the swimmer makes an angle of (0.785 radians) with respect to the line from A to C, as indicated in the figure.

2. Sep 14, 2004

### Sharayah

how the heck do I start???

3. Sep 14, 2004

### Integral

Staff Emeritus
Represent the velocity of the rivers current and the velocity of the swimmer as vectors, use vector addition to find the sum. Drawing a picture helps.

In the future post homework questions in the homework forum.

4. Sep 14, 2004

### Chronos

Insufficient information. What are you solving for, distance from A to B? It sounds like a triangulation problem. The relevance of the river current speed is also unclear since no swim speed is given. If it is assumed the swimmer will arrive at point B given the swim speed, current speed, and initial angle of approach, the problem can be solved by finding the vector angle of the swimmer's path - since you will then have 2 sides and an angle of a triangle.