1. The problem statement, all variables and given/known data How massive an object can be supported by a 5.6 -diameter suction cup mounted on a vertical wall, if the coefficient of friction between cup and wall is 0.65? Assume normal atmospheric pressure. 2. Relevant equations - 3. The attempt at a solution I calculated the maximum force which I realised was when the pressure inside the suction =0 Therefore Fmax=pA=101.3*10^3(pi(0.028^2))= 250N. I don't know how to find the how much mass can be supported by the suction cup. I tried a number of answers and they were all wrong.