1. The problem statement, all variables and given/known data The force constant of a spring is 600 N/m and the un-stretched length is 0.72 m. A 3.2-kg block is suspended from the spring. An external force slowly pulls the block down, until the spring has been stretched to a length of 0.86 m. The external force is then removed, and the block rises. In this situation, when the spring has contracted to a length of 0.72m , the upward velocity of the block is = ??? 2. Relevant equations Conservation of Energy Initial Potential Energy + Initial Kinetic Energy = Final Potential Energy + Final Kinetic Energy 3. The attempt at a solution 0 + 0.5(600)(0.14)^2 = 0.5 x 3.2 x v^2 + 0 v = 1.92m/s? This is incorrect. The four options given are a) 1.0 m s b) 5.1m s c) 7.4 m s d) 9.1 m s e) 9.7 m s Do I need to account for gravitational potential energy in the equation?