1. Relevant information This is a two-block-system on top of each other to the right side of a wall, both attached with springs that are also attached to the wall. A force is applied on the bottom block to the right direction, frictions occurred on both bottoms of the two blocks. Here is the diagram illustration: http://i62.tinypic.com/291ytxt.jpg (BTW, don't worry about Weight = Mg, this can be ignored) 2. Question Draw a free body diagram and determine the equations of motion for this system 3. The attempt at a solution This is the free body diagram I drew: http://i60.tinypic.com/2zdqhpt.jpg According to my free body diagram, I have the equation of motion for this system. M2X2’’ + K2X2 + B2(X1’ – X2’) = 0 M1X1’’ + K1X1 + B1X1’ = f + B2(X1’ – X2’) Does this seem right? Please let me know. Thanks!