1. The problem statement, all variables and given/known data Hi Say I have a spring system as in the attached figure (it is in equilibrium). I am a little confused about the "axial force" concept after reading an example in my book. It goes as follows: "We have the three springs, where the outer most ones are attached to a wall. We look at the four nodes. Now, at node 2 we apply an axial external force F2 pointing right. The force F3 is zero, since there is no external force at this node". They then go on to calculate the reaction forces F1 and F4, and naturally they point left. So they set F3=0 since "there is no external force at this node", but there is no external force at node 1 and 4 either, but yet F1 and F4 are different from zero? This I don't seem to understand. Isn't there a reaction force at node 3 too? Cheers, James.