# Homework Help: Relative Speed

1. Sep 19, 2009

### StephanieF19

1. The problem statement, all variables and given/known data
Two boats are heading away from shore. Boat 1 heads due north at a speed of 3.43 m/s relative to the shore. Relative to Boat 1, Boat 2 is moving 39.6 ° north of east at a speed of 1.02 m/s. A passenger on Boat 2 walks due east across the deck at a speed of 1.58 m/s relative to Boat 2. What is the speed of the passenger relative to the shore?

3. The attempt at a solution
I'm completely confused I just need a starting point. I know this is a multi-step problem I'm just unsure of what I should do first. Do I need to find x and y components of the boats' paths?

2. Sep 20, 2009

### Andrew Mason

This is a slightly tricky vector addition problem.

To solve it you have to first find Boat 2's velocity relative to the shore. Hint: how is the relative velocity of Boat 2 to Boat 1 related to the velocity vectors of Boats 1 and 2 relative to the shore?

Can you use the same technique to then find the velocity of the passenger relative to the shore?

AM