A massless string is wrapped around a solid cylinder. A block of mass m=2.0 kg hangs from the string. When released, the block falls a distance 82 cm in 2.0 s. Calculate the mass of the cylinder. Okay, for this problem, I started off with drawing free body diagrams for the block and the cylinder. I calculated the acceleration for the block to be .41 m/s^2, the final velocity of the block to be .82m/s and the force of tension of the string to be 20.42 N. Now, I think I need to calcuate the radius for the cylinder. Can I use the equation a=v^2/r to do that or is that the acceleration that is going towards the center of the cylinder? Thanks for the help.