Hi, I am trying to simulate the wheelchair, first as a box, and I have made the geometrical derivations from the free body diagram. I have derived my equations, however, could anyone proof read the eqautions? I tried to use them, but the computer programs tell me that my equations are wrong. The first picture is the static fbd of the object, with the dynamic fbd when the force is applied. https://lh6.googleusercontent.com/Z0IZVF1xe9afhk6BvijHVTCDkoqI6a7ew0mJJLYi3Lo4KeOzOlCYIsS8adX1TVC-A5R_8qqJgIgW3F3uLzOQASB2s1K0ba9nxwhKisdKubmuldXJUqxYkTtl1Q [Broken] This one is the derivations (alpha, and alpha dot are fixed) https://lh5.googleusercontent.com/fuvMwEE0ITERgSTKdXSic2NL6vtUJ53Zr-dIT3nau7mZMvikgmypkXpelzTglsYlyXcG8rfXZOR-8jTcFo6Nacdb3EVTbdFcslhri42GB3DEoycwRUtsVmjFAQ [Broken] Thank you so much!