(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A: A boat capable of making 11.0 km/h in still water is used to cross a river flowing at speed of 3.0 km/h. At what angle (in o) must the boat be directed (from the perpendicular to the shore) so that its motion will be straight across the river?

B: What is the resultant speed relative to the shore?

2. Relevant equations

I'm not sure of the Exact Equations.. Possibly

Ax = A*cos(Theta) Ay = A*sin(Theta)

Bx = B*cos(Theta) By = B*sin(Theta)

Ax+Bx=Cx .. or Ax-Bx=Cx

(I'm at work right now, I forgot the last equation .. Ay/Ax = The tangent of Theta ? By/Bx)

3. The attempt at a solution

For my solution I drew a vector triangle. One directly North, one at the head of this vector going to the right (east) .. and then a resultant line connecting these two vectors. Mainly I just divided 11/3 and took the tangent of this, but couldn't find the correct answer. I can't really attempt the 2nd problem without the way to do the first.

Thanks in advance for the help :)

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Boat Crossing the river

**Physics Forums | Science Articles, Homework Help, Discussion**