1. The problem statement, all variables and given/known data This formula we've been using recently, I don't understand where it comes from. 2. Relevant equations T = 2pi * sqrt(m/k) 3. The attempt at a solution Hooke's law: F = -kx E(total) = .5mv^2 + .5kx^2 Circumference of a Circle: C = 2 * pi * r I figure these piece together, but I don't understand how.