1. The problem statement, all variables and given/known data In t=0 a car is free from it's chain and can fall freely through a inclined plane (10 degrees) rear wheels weight 500 lb each one and have an diameter of eight feet. Front wheel weights 800 lb and have a radius of 2 feet. The body of vehicle weights 9000 lb. Assume that wheels can drift. Obtain a expression for velocity in function of time. 2. Relevant equations Summation of forces = ma We have inerce forces and gravity force. gravity force exerted on vehicle equals to Mgsin10 3. The attempt at a solution inertia force formula is Ia, then I should add the forces. M*g*sin(10)+Ialpha=Ma 5.591471 ft/s^2+Ialpha/M=a alpha is angular acceleration. A condition for simultaneous rotation and translation movement is v=wr w=v/r dw/dt= 1/r(dv/dt) 5.591471M+I(1/r) dv/dt=Mdv/dt and Inertia applies for each rotating element 5.6M+(I1/r1+I2/r2) dv/dt=Mdv/dt 5.6M+(I1/4+I2/2)dv/dt=Mdv/dt Moment of inertia for a wheel=mr^2/2. M is the total mass in the system. 5.6M+(mr^2/2+md^2)/4+ (m1r1^2/2+md2^2)/2))dv/dt=Mdv/dt 5.6M+( (8m+md^2)/4+(2m1+md2^2)/2)dv/dt=Mdv/dt 5.6M+( (8000+1000d^2)/4+(1600+800d2^2)/2)dv/dt=Mdv/dt D are distances from the axis, they are unknown. I only should put the expression from dv/dt and integrate for get a expression for v in function of t. I don't know if my solution is right/ In which step I am wrong?