1. The problem statement, all variables and given/known data The acceleration 'a' of the supporting surface required to keep the centre G of the circular cylinder in a fixed position during the motion, if there is no slipping between the cylinder and the support will be? 2. Relevant equations 3. The attempt at a solution The torque acting about the point of contact of cylinder and surface is equal to the product of angular acceleration and moment of inertia about the point of contact. observing from the frame of the supporting surface, a pseudo force ma acts up the incline plane. (mgsin(theta) -ma) x radius=(3mr^2)/2 x a [ I about the point of contact is (3mr^2)/2 ] on solving, a=2gsin(theta)/5 but the answer is 2gsin(theta). Please help.