1. A solid disc of radius r, is rolling down a variable incline (a ramp). Show that the acceleration of the centre of mass, C is given by: a=g[ sinθ – F/Ncosθ ]. I have done this as shown below. N is the normal reaction and F is friction. N = mgcosθ F = µN = µmgcosθ mgsinθ – F = ma mgsinθ – µmgcosθ = ma a = g[ sinθ – µcosθ ] but µ = F/N a=g[ sinθ – F/Ncosθ ] 2. Determine an expression for the value of F/N where the only unknowns are the angle θ, the radius r and radius of gyration k. I have tried this question and can’t get the right answer and need some help please. I know T = Iα I = mk2 also for a solid disk I = 0.5mr2 α = a/r m=N/gcosθ Can anyone help with this question please?