1. The problem statement, all variables and given/known data The figure shows a cord attached to a 2 kg cart that starts from rest and can slide along a frictionless horizontal rail. The right end of the cord is pulled over a frictionless pulley at height h = 2.0 m above the point of attachment of the cord to the mass, so the cart slides from x1 = 4.0 m to x2 = 1.0 m where x is measured positively to the left from a line that passes vertically through the center of the pulley. During the move, the tension T, in the cord is a constant 49 N. What is the speed of the cart (in m/s to two decimal places) when it reaches x2 ? Image: http://drbensonphysics.org/file.php/3/AP_images/variable_force_constant_tension_.jpg [Broken] 2. Relevant equations F=ma v^2=2aΔx 3. The attempt at a solution I understand that the force on the object varies due to the changing angle of the applied force, and that the relevant component of the force is equal to the cosine of the angle. I found this to be Fcos(arctan(2/x2-x1-D)) where D is the distance the mass has traveled at any given point in time. I don't have any idea where to go from here because it seems that I must keep substituting the same equation into itself if I use a = F/m. Thanks for any help.