1. The problem statement, all variables and given/known data A mass of 100 g is tied to the end of an 80.0 cm string and swings in a vertical circle about a fixed center under the influence of gravity. The speed of the mass at the top of the swing is 4.00 m/s. What is the tension in the string when the mass is at the bottom of its swing? 2. Relevant equations 3. The attempt at a solution I really don't even know where to start! Please help.