<s>[INST] This problem concerns multibody mechanics, one of the fields within the broader realm of mechanical engineering. The purpose of this exercise is to help the student understand how to perform a static analysis on a multibody system with frictionless contacts. Problem statement: A group of links connected by revolute joints to each other are required to analysis an internal force within the multibody system. For example, given the described four links system with an applied static distributed load, F(x, y, t )=3sin(4πx + π/4), and parameters: 
L1=3m, L2=2m L3=4m, L4=5m, m1=10kg, m2=20kg, m3=7kg, m4=12kg 
It is needed to compute the minimum of the internal force within the link's connections. The system in question exhibits planar motion and the references frame can be considered planar with the positive Z direction pointing out of the paper. 

* Notes: The requirement using symbolic expression F (x, y) instead of numerical value. 
Here is an FBD for the first body 
Am I able to solve this using mechanics of materials or do I need to use motion equations for this problem?[/INST]