Would anyone be able to give me a hint for this question? Do I take the integral? I have possible answers but I am unsure. A rod of length 30.0 cm has a linear density given by: D = 50.0g/m + 20.0xg/m^2 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?