Impossible Physx Homework!! I have a few problems left that I'm completely stumped on how to do. #1) A typical lab centrifuge rotates at 4000rpm. Test tubes have to be placed into a centrifugre very carefully because of the very large aceelerations. What is the acceleration at the end of a test tube that is 10cm from the axis of rotation in? #2) A 5m-diameter merry-go-round is initially turning with a 4s period. It slow down and stops in 20s. Before slowing what is the speed of a child on the rim? How many revs does the merry-go-round make as it stops? Out of my 6, these trouble me the most. For #1, I made the radius 10cm, the velocity constant, but am unsure what equations I need to plug those in. As for #2, it's thet same deal. In one, I have the period, and in the other I'm left with the velocity, and with both I have the radius, but have no idea where to put them. Please, help with a point in the right direction.