The discussion revolves around determining the value of F2 in a physics problem involving forces on an inclined plane. The original poster has provided a free body diagram and a set of equations but is struggling to find the correct solution.
The conversation is active, with participants providing guidance on how to approach the problem. There is no explicit consensus, but several suggestions have been made to help the original poster refine their understanding and approach.
Participants note that the object is at rest, which implies that the forces must balance out. The original poster's equations are questioned for clarity regarding the signs of the components.
Pupil said:Rotate your axis so that the F1 and F3 are exclusively in the x plane. From there it should be easy. You know the force of gravity, and you can find it's i and j components and solve for the rest. That's the trick to these inclined plane problems -- choose your axis wisely.
kuruman said:First draw yourself a coordinate system (x and y axes) so that we can talk about components of vectors. For a problem of this sort, x is usually along the incline and y perpendicular to it.
Once you've done that, find the components of each vector. Since the object is at rest, the sum of all the x components must be zero and the sum of all the y components must be zero.
Note that for a sum of two terms to be zero, one term must be positive and the other negative. Your equations do not show that, With a coordinate system drawn, it should be easy to see which components are positive and which are negative.