# Homework Help: 2 dimensional acceleration

1. Sep 28, 2008

### chris097

1. The problem statement, all variables and given/known data

A watercraft with an initial velocity of 6.4 m/s [E] undergoes an average acceleration of 2.0 m/s^2 for 2.5 s. What is the final velocity of the watercraft

3. The attempt at a solution

i'm lost :(

2. Sep 28, 2008

### LowlyPion

Welcome to PF.

What equations do you know that would relate velocities and acceleration and time?

3. Sep 28, 2008

### chris097

Vf = Vi + aav(t)

and thank you for the welcome :)

4. Jan 28, 2009

### mattstjean

That equation doesn't work. It's 2 dimensional. South acceleration with an Eastern intial velocity. I've been on that question for way too long. Please help.

5. Jan 28, 2009

### LowlyPion

Starting from rest then what will the {S} component of velocity be after 2.5 s?

The V = a*t cited would work just fine.

Armed with the {S} velocity and knowing that the {E} velocity is unchanged, then simply add the velocities as vectors. Let Pythagoras be your guide.

6. Jan 28, 2009

### mattstjean

oh my... thanks a lot. i'll be able to sleep tonight now.