1. The problem statement, all variables and given/known data A car and a trailer are connected by a joint. The car and trailer system are on a inclined place at a gradient of 8 degrees. The rolling friction coefficient along with other vehicle parameters are given.We are asked to draw the free body diagrams of the car and trailer separately and thereby find the forces at the joint. 2. Relevant equations Splitting the car-trailer system into 2 separate free body diagrams. 3. The attempt at a solution I am finding difficulty as to how I should position the forces in the free-body diagram.I have made a logical guess in the solution attached as I assume there is 'dynamic equilibrium'(just as is taken in the D'alembert principle). Am I right in the way I have shown the direction of the joint forces? Can it be done in the exact reverse sense and still be correct? In the whole system diagram,it does make sense for the joint forces to be so as the joint sags downwards and is pulled forward.