Two forces acting on an object given in vectors - SOLVED

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The discussion focuses on applying Newton's second law to analyze two forces acting on an object. The user splits the forces into F1 and F2, using the equation F1 + F2 = ma. They derive F2 by rearranging the equation and substituting the mass and acceleration terms. Another participant suggests considering the forces as components in the I and J directions to clarify the calculations. This approach emphasizes the importance of breaking down forces into their vector components for accurate analysis.
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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
 
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Have you tried to look at it as components I and J as:

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

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