Finding Other Force in 2-Force Problem

[k31453]

Other Force problem !

Homework Statement

Two forces act on a 3.1 kg mass, which undergoes acceleration a = 0.88 i - 0.28 j m/s2. If one of the forces is F1 = - 1.5 i - 3.0 j N, what is the other force?

Homework Equations

I don't know how to visualize this !

The Attempt at a Solution

I know two component add to Force but I can't visualize. I know vectors as :
F2 = ( 0.88 i - 0.28 j) * 3.1 which is 4th quadrant and F1 will be 3rd quadrant but how i can visualize it !

 

[BruceW]

yep. One force is a vector which goes to the third quandrant, and the total vector is in the fourth quadrant. So how to get from the third quadrant to the fourth quadrant? maybe it is simpler than you are thinking.

 

[k31453]

Ok how do you know that's total vector ?

 

[BruceW]

well, you got it by multiplying mass times acceleration, so by definition, that is the total force vector.

 

[k31453]

Cause... that's where i was gettin tricked.

 

[SteamKing]

Well, did you try making a sketch?