1. The problem statement, all variables and given/known data Keys with a combined mass of 0.100 kg are attached to a 0.25 m long string and swung in a circle in the vertical plane. What is the tension in the string at the bottom of the circle? Known: Mass = 0.100 kg Radius = 0.25 m 2. Relevant equations Fc = mv^2/r 3. The attempt at a solution I know I need to find the velocity at the bottom to put it into the equation. I just don't know how to figure out the velocity at the bottom, I know the velocity at the top of the circle is 1.56 m/s ^ 2 Any hints or tips on to what I should be doing?