1. The problem statement, all variables and given/known data There are two balls with masses m_a and m_b connected by a string. m_b is moving at a velocity v upwards (perpendicular to the string) and it asks for the Tension (T) in the string. 2. Relevant equations a=(v^2)/R delta Energy of system = 0 T = m((u^2)/r) u is linear speed of rotational motion r = radius of motion 3. The attempt at a solution The initial kinetic energy of m_b = .5(m_b)v^2 and that's as far as I got. Is mass B moving? how do I start this problem?