# Projectile Motion Sail Boat

1. Mar 8, 2008

### Kster

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

A sailboat is traveling east at 5m/s. A sudden gust of wind gives the boat an acceleration 0.8m/s^2 (40 degrees north of east).

1. What is the boat's speed 6 seconds later when the gust subsides?

2. What is the boat's direction 6 seconds later when the gust subsides?

2. Relevant equations
v = v0 + at
A^2 + B^2 = C^2

3. The attempt at a solution

I'm so stuck, please tell me what I did wrong.

Last edited: Mar 8, 2008
2. Mar 8, 2008

### tiny-tim

Hi Kster!

Your v_0 shouldn't be 0 (it would only be 0 if the wind was North or South).

Try again!

3. Mar 8, 2008

### Kster

Thank you for replying, ok so I fixed it:

The Opposite Side:
Vo + at = V
(5m/s?) + (0.8 m/s^2 * 6 sec) = 9.8 m/s

My question is, is 9.8m/s my answer to the boat's speed 6 seconds later? or Do I have to use the Pythagorean Theorem to figure out the Hypoteneuse side and that is my answer?

4. Mar 8, 2008

### tiny-tim

No.

You must do everything in the same direction.

The acceleration is at 40º, so you must use the component of initial velocity along that direction too (using cos).

You then use Pythagoras to combine that result with the perpendicular component of initial velocity (which will be unaffected).