1. The problem statement, all variables and given/known data I'm asked to solve the typical intro level box on an inclined plane problem but I need to do it using the lagrangian. My difficulty with it is that the axis I am required to use are not the typical axes used when solving this using Newtonian mechanics. Instead of the x(or y) axis being along the incline with the other perpendicular to it, the axes here are the x-axis going from the high end of the incline to the low end and the y axis from the top to the bottom (so x is horizontal facing left and y is vertical facing down) I am then asked to compare the answer using lagragian to the answer using newtonian stuff. http://i.imgur.com/OAosTDI.png 2. Relevant equations 3. The attempt at a solution I've tried a billion different ways and always and always end up with the acceleration in the y direction being g(sin(a))^2 and in the x direction g(sina)(cosa). On one hand it makes no sense since obviously the acceleration in the y direction should be just g but on the other hand it makes sense because if we find the acceleration along the incline it is clearly gsin(a) as doing with a the typical coordinates of x along the incline would show. Then, if the acceleration is gsina along the incline, breaking it into components along the x and y axes would multiply it further by another sina in the y direction and cosa in the x direction which shows the same thing I got using the Lagrangian method. So I have been going in circles with something that makes sense yet doesn't make sense.