I was wondering if anyone can provide feedback on my free body diagram of two objects acting on each other. The question is asking for two separate free body diagrams. A force is applied to object 1, and object 1 pushes against object 2. Object 1 is on wheels and object 2 is in contact with the ground. The two objects accelerate. Find the constant for the kinetic friction. I can confidently find the constant, as long as my free body diagram is correct. But, I would like some feedback on whether it's correct it or not. On object 2, the vertical force is in equilibrium, F2N - w2. The horizontal force is F1 ON 2 - fk. On object 1, the vertical force is also in equilibrium F1N - w1. The horizontal force for object 1 is a bit confusing. I'm assuming it's nearly frictionless, since it's on wheels. So is it, F - F2 ON 1? I guess it would be incorrect to subtract fk from the horizontal force on object 1, since it's only acting on object 2, however how does that friction force affect object 1?