Hey Forum I'm hoping someone can help me gain some clarify with this problem. This is related to the trolley design thread i created; however this is a different problem so i thought it best to start a new thread. Hope that's ok. Basically, i want to analyze a basic rigid frame for a 4 wheel trolley to determine the internal member forces and perform the usual analysis to determine the ideal beam design and material. Under normal operation, the operator will apply a horizontal push force (F = 225N) on the horizontal handles, which will move the trolley forwards. I'm familiar with analyzing frames in static equilibrium as I've done plenty of these as homework before. However, because the trolley has 4 wheels, the frame reactions will be purely vertical (to balance the cargo load applied, W = 2943N, concentrated as L/2). Everything's fine as long as no external horizontal forces are introduced into the frame analysis. If i introduce the push force in the FBD however (see image below), the frame will no longer be in static equilibrium, as there are no horizontal reaction forces to balance it out. My initial approach was to lock the rear wheels so they act as a simple fixed supports; that way the rear wheels would be able to balance the horizontal push force (assuming the brakes are able to handle this force without slipping). However this has given me some inconsistencies in my analysis, with some of the internal forces being different depending on how i solved for them (which doesn't make sense). This leads me to think that maybe I'm going about it the wrong way (i'm fairly certain i'm not just doing bad math). What would be the best way to perform a frame analysis for this type of wheeled problem? I thought i might be able to google how similar moving frames are analyzed (car and bike frames for example), however i wasn't able to find anything helpful. Assuming the frame is moving horizontally doesn't seem right as I'd then have to deal with horizontal acceleration. Alternatively i thought maybe just remove the wheels and analyze the frame with both A & B as simple fixed supports instead (with horizontal and vertical reactions). However i'm not sure if this would be the best approach either. Any ideas would be appreciated.