Two forces acting on an object given in vectors - SOLVED

[runningphysics]

Homework Statement:

Two forces act on a 3.4 kg mass and undergoes an acceleration a= .87i - .32j m/s^2. One force is F= -.7i - 3.0j N. What is the other in terms of i + j?

Relevant Equations:

F=ma, F1 + F2= ma

I tried splitting the forces up into F1 and F2 making Newtons second law equation into F1+F2=ma. Then I added over the the first force given. multiply the mass to the acceleration terms to get F2= (m*ai + m*aj) - F1

 

[jedishrfu]

Have you tried to look at it as components I and J as:

$F1_i + F2_i = m a_i$ and similarly for j