1. The problem statement, all variables and given/known data If a rotational object is moving from rest to 200rpm in .23 seconds, the acceleration is? 2. Relevant equations a = V^2/r v = 2Pi(r)/t I am sure there are others, but this is just a General Physics I course, so its dealing with Newton and Kepler's laws. 3. The attempt at a solution To be honest, I dont know if it is totally solvable. I have a feeling that I am going to be left with a variable in my answer since the radius is not given. Without a radius, I cant figure out velocity, and without velocity I cant figure out acceleration. Judging by previous questions of my professor, the answer would most likely be in meters/second. Working with radius as a variable, I am getting something like this: a = (2π /.23)² r Would this be logical, or am I going about this in the wrong way?