1. The problem statement, all variables and given/known data The assignment is for a lab, we were to take an incline plane, and push a cart up the plane and measure the acceleration (using software). We need to use the difference in the accelerations (when the cart is moving up the plane and then back down) to find of the force of friction. We first had to develop two equations for the accelerations, up and down. I have them as axd=g(sin(θ)-μcos(θ)) and up, axu= g(sin(θ)+μcos(θ)). I think those are right, I just changed the sign because when the cart is going up the track the force of gravity should be working with the force of friction to increase the total acceleration pulling the cart back down. However if those aren't right please let me know! My main problem however has come from trying to solve both equations for the variables g and μ. The problem is we have to combine them and solve so that only the measured accelerations, θ and one of the variables (either g or μ are present). Once doing that I should end up with two equations that independently allow me to solve for either g or μ 2. Relevant equations 3. The attempt at a solution After spending a lot of time trying to combine and solve the two acceleration equations I got g = (axd+axu) / (2sin(θ)) μ = tan(θ)((axu-axd/(axd)+axu) I'm not even sure if I did completely legal math when trying to solve the two equations. The reason I'm having so much trouble could be that my acceleration equations are wrong, but they seem to check out with all the research I did. Any insight into my problem would be greatly appreciated, thank you.