Two-Dimensional motion components

[wallace13]

A wild horse starts from rest and runs in a straight line 29° north of west. After 27 s of running in this direction, the horse has a speed of 15 m/s. Find the magnitude of the horse's average acceleration. Assuming that north and east are the positive directions, find the component of the horse's acceleration that points along the north-south line. Find the component of the horse's acceleration that points along the east-west line.



Vf= at

sin O= opp/hyp

cos O= adj/ hyp

I found the average acceleration to be .56 m/s north of west using the first equation. I would assume that the the x and y components it asks for would be found using the sin and cosine equations, but i get the wrong answer ( .29 m/s and .49 m/s)

 

[Mattowander]

How do you know that that is the wrong answer?

 

[wallace13]

Because we type our answers into webassign.net and it tells us if we're right or wrong.

 

[Mattowander]

The problem states that North and East are defined as the positive directions. However, the resultant acceleration of the horse is north of WEST. Therefore, one of the components will be negative.