First off, apologies if this is in the wrong forum, if my notation is terrible, or any other signs of noobishness. I just started university and I'm having a hard time with my first Lagrange problems. Help would be very much appreciated. 1. The problem statement, all variables and given/known data A body of mass m is lying on a smooth, frictionless plane. The plane, which is originally horizontal, is lifted up at one end at a constant rate such that the angle of the plane with the horizontal at time t is θ = at. This problem comes with a diagram which includes an arrow pointing down labled g. I presume this is a constant force g from gravity? 2. Relevant equations I need to show that the lagrangian of the body, expressed in terms of the distance q from the base of the plane where it hits the horizontal, is L = 1/2(mqdot^2) + 1/2(ma^2q^2) - mgqsin(at) Also, determine the Euler-Lagrange equations for the system 3. The attempt at a solution I understand that L = T - V and T = 1/2(mqdot^2), V = 1/2(kq^2); but after that, I'm just not sure what to do to make it look like it's presented in the problem. I'm not even sure what k should be for V. ma^2 ? If so, could someone explain why? Thank you very much for reading.