1. The problem statement, all variables and given/known data 2. Relevant equations Conservative of energy mg(y2-y1) +1/2 k (s2-s02) = 1/2 mv12 +1/2 mv22 3. The attempt at a solution v1 = 0 at rest y2 = 0 bottom What I got is v2 = 8.20 m/s but not correct, I don't know how I can take into account the tension.. Fspring = -ks = -4000 N/m * 0.2 m = 800 N at position 2, isn't it? why it says 500 N?