1)If I head across a river paddling my canoe at 6km/h N, but the river current is moving at 3km/h E, determine the speed and direction of my canoe relative to the shore.

Printable View

- Jul 20th 2008, 11:01 AMjimCproblem solving with triangles.
1)If I head across a river paddling my canoe at 6km/h N, but the river current is moving at 3km/h E, determine the speed and direction of my canoe relative to the shore.

- Jul 20th 2008, 02:48 PMabender
1)If I head across a river paddling my canoe at 6km/h N, but the river current is moving at 3km/h E, determine the speed and direction of my canoe relative to the shore.

This is simply a vector addition problem. The resultant vector will be the hypotenuse of the right triangle you construct as well as its direction.

The math bit: $\displaystyle 6^2 + 3^2 = h^2 $

So, $\displaystyle 36 + 9 = h^2 $

$\displaystyle h^2 = 45 $

We are only concerned with the positive root. Thus, h = $\displaystyle \sqrt{45} $

So, your speed and direction is $\displaystyle 3\sqrt{5} $ km/h NE .

-Andy