# Homework Help: Find the magnitude even though direction is correct?

1. Sep 7, 2010

### rfig08d

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

The force exerted by the wind on the sails of a sailboat is 490 N north. The water exerts a force of 250 N east. If the boat (including its crew) has a mass of 250 kg, what are the magnitude and direction of its acceleration?

2. Relevant equations

V= SQRT(X2+Y2)
Tan-1(Vy/Vx)

3. The attempt at a solution

Drew it out on a piece of paper:
(0, 490N)
(250, 0)
So: (250, 490)

Direction = tan-1(490/250) = 62.96

Magnitude = V = SQRT(490^2+250^2) = 550 = Wrong?
Why would the magnitude be incorrect? Or can anyone point out where I may be wrong?
Thank you!

Edit - The answers are supposed to be in acceleration (m/s^2) and my magnitude came out to be:

550 Kg m/s^2 so I just divided by the kg and got my answer!
Silly mistake ;)

Last edited: Sep 7, 2010
2. Sep 7, 2010

### Redbelly98

Staff Emeritus
Welcome to PF. It's always good to see people who pay attention to units!