This isnt a homework problem, I just have a general problem with solving AS level (M1) statics questions in mechanics that are similar to this example (our teacher have moved on to the next module now but i'm still stuggling with these): example A particle of mass 3kg rests in limiting equilibrium on a rough plane inclined at 30degrees to the horizontal. the coeffiecient of friction between the particle and the plane is 1/3. A horizontal force of magnitude XN is applied to the particle so that the equilibrium will be brocken by the particle moving upwards. Find the Value of X. I always seem to get these wrong and i dont understand why. Here is how i wuld go about it, if anyone can tell me where and why my method is wrong please do! I really need to understand this soon. attempt Fr=1/3R Fr=3g/sin30=58.8N therefore R=58.8*1/3=19.6N and there, this is where i get stuck and have absolutely no idea where to go from now.