I'm just trying to review for an exam and the only thing I don't really get is how to calculate centers of mass. I'll just use two problems I had in my homework that I didn't know how to do. I feel like these two problems should be really easy but I have idea how to do them. 1. The problem statement, all variables and given/known data 1. Find the center of mass of a uniform wire that subtends an arc θ if the radius of the arc is a. My terrible MSPaint picture to give you an idea: 2. Find the center of mass of this isoceles triangle: 2. Relevant equations 1/M [Integral] rdm 3. The attempt at a solution In the first one I tried to use polar coordinates and substitute dm for density*dθ. Density would be M/θ. But when you get to the integral it's 1/θ so you would get the natural log of zero or a negative number depending on how you want to do it. For the second one, I have no idea where to begin even. Would you have to do a double integral and find the equation of the line that forms the triangle or is there an easier way?