# Homework Help: Velocities with angles

1. Nov 22, 2012

### Surgikill117

1. The problem statement, all variables and given/known data
A passenger on a boat moving at 1.5m/s on a still lake walks up a set of stairs at .5m/s. he stairs are angled at 45 degrees in the direction of motion as shown. What is the velocity of the passenger relative to the water.

2. Relevant equations

3. The attempt at a solution
How do I find the horizontal velocity of the passenger. Do I take half of the velocity because the angle is 45 degrees? I don't know which equations I should use to find the passengers horizontal velocity.

2. Nov 22, 2012

### HallsofIvy

If you draw a line representing the surface of the water, a line representing the stairs and draw a perpendicular, you will see a right triangle. ".5 m/s" is the rate of change along the hypotenuse of that right triangle. Do you know how to find the lengths of the two legs of a right triangle if you know the length of the hypotenuse and an angle? Using, say, sine and cosine?