1. The problem statement, all variables and given/known data A rod of length 30.0 cm has linear density (mass-per-length) given by λ = 50.0 g/m + 20.0x g/m2 where x is the distance from one end, measured in meters. (a) What is the mass of the rod? (b) How far from the x = 0 end is the center of mass? 2. Relevant equations Xcm = l/2 3. The attempt at a solution λ = 50.0 g/m + (20.0)(.3m) g/m2 λ = 56 g/m * .3 m λ = 16.8 g Xcm = .3/2 = .15 The actual answers are 15.9 g and .159 m Am I not using the formulas correctly?